Hello all... Interesting thread... sorry I'm late to the party.
I've got a few thoughts and suggestions... if I'm out of line, just tell me to STFU, I'll skulk away.

MamaLiberty... to address your initial premise... and I say this with the utmost respect... Hogwash!
By your own admission, you are unwilling or unable to take the time to learn Linux. That's hardly the Linux community's fault. If you would take just a fraction of the time that you spent to learn Windows over the years, you could free yourself from an ever more oppressive corporate monopoly. You are asking your computer to do a little more than toast your bread or cool your quart of milk, and as such, just a little more involvement is required on your part. The AI of Skynet or the Starship Enterprise doesn't exist yet.
The commercialization of Linux seems to be an issue... to ease your concerns, there are commercial versions of Linux available.... Redhat, SUSE, Xandros, Linspire, just to name a few. There are companies that sell Linux configured systems or laptops... IBM (at least they used to, not sure if Lenovo still does), Dell, maybe even HP.. and there are others, that escape me at the moment, but I'll look them up if requested) The concept that software is free is pretty radical, but true. Just because it's free, doesn't mean that it's not commercially viable or that you can't pay for it if you want to. Every author of Open Source Software (OSS) that I've ever seen will accept contributions for their work... not mandatory, but encouraged. These are people that volunteer their time to work for the good of the community and the love of their craft... they gladly accept donations to keep the project alive. If you use Ubuntu, and they don't accept donations, then contribute to Debian. As far as support is concerned, you can purchase commercial support from Canonical (the K/Ubuntu people)
http://www.ubuntu.com/support/paid If you go to a large bookstore (Borders, Barnes&Nobel, etc) they usually have a few Linux magazines in the computer magazine section... or go to amazon.com and search for books on ubuntu or red hat or some of the other popular distros, they exist and can help. My point is, Linux support systems exist.
Microsoft hasn't released an OS that's been ready for prime time in decades... since MS DOS 3.3, IMHO

Even though they spend untold $$ and have an army of Beta testers, every modern release of their OS has had problems... they stand ready, of course, and release updates to fix the issues... but the problems still manifest. No corporate IT department updates their MS desktop users to the new release for AT LEAST six to twelve months... sometimes longer. They wait for the all the bugs to be worked out before the pain of a corporate upgrade. Unfortunately, Microsoft has the lion's share of desktop computer OS installations. But, this isn't by chance. They've always bullied and used anti-competitive measures to coerce vendors and partners to ensure that new systems go out the door with an MS OS installed. That is one reason (but not the only one) that you don't find Linux on as many desktops. And I can't tell you how many times a "fix" from MS has made the problem worse... in fact the rule of thumb is to wait to do any upgrade provided by MS for at least a week, unless it's a high priority security fix (then pray!) One other thing that may or may not concern you is the M$'s alarming trend to control you, your computer, your data and your use of copy-righted material (Movie DVDs, music CDs) through DRM restrictions. One reason that you need a new, robust computer system to run Vista is that M$ is using the increased, raw CPU potential to make sure you are not violating any DRM restrictions or violating any Intellectual property standards, as defined by corporate industry and government, not you. I've read that the system even has the capability to phone home if it's determined that you've gone against the grain, and then the MotherShip can lock you out of your own system. Not to mention the rumors of NSA involvement and back-doors in the system. This should concern any freedom-minded person. If past performance predicts future trends, then this is only going to get worse. If however, you can't find a suitable replacement for Dreamweaver (
http://www.osalt.com/dreamweaver ), then I would recommend that you keep the old computer with Windows and Dreamweaver on it, do your development work, copy your files to a USB key or hard drive to transfer to your Linux system, and upload them from there. Don't connect it the Internet... if you're not updating the security on a windows system anymore, it's only a matter of time before the system will be compromised by a virus, trojan or exploit. Just my $.02. Oh yeah... have you ever read the EULA (End User License Agreement) that you have to agree to in order to install Windows on your system? If you haven't, maybe you should... you may be surprised at what you've agreed to with M$.

Linux has made great progress on the desktop. The install program allows you to partition the hard drive, and install along-side Windows by dual booting (something a MS install doesn't do.) I find it easier to do a simple install of Linux than XP. Coming from a Windows environment, I would recommend that you use the KDE desktop, instead of Gnome... It's more "Windows" like and more configurable than Gnome. In the case of Ubuntu, that would mean use Kubuntu instead... same Linux, different windows manager. I prefer to use a Debian based distribution because Debian is a very solid, stable distribution, it's package management system is arguably second to none and the shear number of packages available to a Debian system is fantastic. Truly a win-win for the new Linux user. That being said, I would use either K/Ubuntu, Mint or Mepis.
ML, I'll extend the same offer as Myrkul (just in case he's hit by a bus (no offense Myrkul... just a odd sense of humor here))... and help support you where needed.
And, depending on how you want it set up (dual boot, or just replacing your old hdd), it could be just as easy as pulling the old drive and replacing it with the new.
Stop the choo-choo for a minute. This may or may not work depending on ML's hardware and what Myrkul uses to configure the HDD on. You have to make sure that the E-machine's chipsets (support, integrated sound, video, etc) are supported on Linux and are loaded by the kernel. Not trying to rain on the parade, just pointing out some potential issues... and ML, before you go A-HA... the same thing has to happen with Windows, it's not endemic to Linux. Linux's modern HAL and dbus systems are pretty good and chances are, you won't have too many problems, but the potential exists. The only true way to make sure is for Myrkul to configure Linux on the same system you have or to ship him your tower (case only, no need to send the monitor, keyboard, mouse... he probably already has them.) The other stickler that I can see is possibly the modem ML has installed in the system. What make and model? Is it a winmoden? If you are going to switch to Linux, and use a modem, probably the best thing to so is to purchase a real, external modem that is know to work with Linux. You can use this type of modem on a Win or Linux system... and if problems arise, they are easier to troubleshoot. In order to cut costs, winmodems don't have all the processing hardware and code built in, the driver uses the host computer to do the processing (in this case, Windows.) These modems usually don't work with Linux... propriety drivers don't exist for them.
Myrkul, whatever approach you use, I suggest that you configure the SSH server on the system and a generic, unique user account, so that you or I or someone else that ML trusts can remotely access her system after she gets it to provide remote support, if needed. The SSH server can be turned off and/or firewalled when not in use and the user account can be disabled after the fact... so there shouldn't be any security worries.
In any case, MamaLiberty...sorry for the geek-speak, it couldn't be helped. Let me know what I can do to help.
Mr. Badger... are you reading this also?