Have you updated to Windows Vista yet? I was forced to when I needed a new computer. Fortunately I have an older laptop running XP or I'd probably have jumped out the window. [It's only about 6" to the ground.] As it was I tore my hair out. Six months later I still prefer the old XP computer.
Several programs I use daily [not genealogy programs] do not work and were expensive upgrades, Adobe Acrobat Pro being one of them. There were some problems with hardware too including drivers for printers, scanners, etc.
I use TMG [The Master Genealogist]. The current version works with Vista with a few minor tweaks. I did check that out in advance of the install because in this case you need to know those things before installing. I also own Second Site, a program that works with TMG to create web pages. It works with Vista.
The latest version of GenSmarts works with Vista. GenViewer from MudCreek seems to work but GenMatcher does not. I like GenMatcher for comparing two GEDCOMS. Yes, I know other programs I own, including TMG, can do it but I like the way GenMatcher does it.
I have an old program which I believe is called Places. You type in a town name and state. The program tells you what county that town is in. Surprisingly it works just fine. I don't have a place in the US without a county in my TMG database because of this nifty program.
I use a Palm LifeDrive and GedStar Pro. GedStar Pro contains my entire TMG database in my pocket. Palm does not work with Vista and therefore neither does GedStar Pro. The only option is to switch to a Windows based PDA and a Windows PDA genealogy program. That's expensive, not to mention replacing all the other software I've come to depend upon in my 10 years with Palm. I also have several genealogy books on my Palm for reading on the go. I'm not giving it up any time soon.
Family Tree Maker says it works with Vista. I haven't tried it.
If you are considering a new computer it is going to come with Vista and you are going to have as much "fun" learning the system as you can stand. Vista is to XP as a dog is to a spider unfortunately. Make sure you know upfront what programs and hardware you need to replace, update or learn to live without. More importantly, make sure your genealogy software is compatible or can be made compatible with an upgrade or a tweak. Changing programs with database is not something to take lightly.