Hi,
I have a Vista PC at work and it is reasonably stable, possibly more than my XP system was. I have 2gb ram and I havve to admit, it could do with more but then I have this problem with never closing apps or rebooting the system.
There are lots of nice features in Vista, apart from the fact that it looks pretty. I think the visuals are just a gimmic. IE7 is better too with the tabbed browsing, helps keep things neater. I have a work related browser, a non-work browser and another for things that I dont leave open.
Hardware wise, I have never had a more reliable system than an IBM/Lenovo. They are built like tanks and are easy to upgrade. You also have the best technical resource for drivers, manuals etc on their website. Second to IBM/Lenovo would be HP/Compaq. They arent as well built but they too have an excellent website. As far as I am concerned, they are the only good PC manufacturers when we had our tests a few years ago. At the bottom of the list was Dell. Poor build quality, too plasticy and you can order 2 Dell PCs, same spec but they often have subtle differences like motherboard or graphics card which is fine if you have one but when you have 200 of them, it is a nightmare. Their website is a bit naff too.
Failing that, if you are a meddler, get one built up by your corner PC shop. Just make sure you know what is going in it and get all the boxes and drivers so you can do an easy rebuild later should you need to.
Failing that, build your own. It's not that difficult as long as you are methodical and organised but you are on your own when it goes wrong.
Good luck!
