If you aren't planning on playing any games, you don't need a super expensive graphics card. You can buy a simple £50 card and it will perform exactly the same as a £400 card in windows, obviously games will benefit from a more expensive card. Something like an 8500GT will most likely do exactly what you need which leaves more money for RAM, CPU, Mobo etc.
I doubt you'll need an SLi or Crossfire motherboard (i.e. it has two slots for graphics cards), because it doesn't sound like you're a hardcore gamer. Those systems mean you buy two graphics cards and link them together which is probably overkill for what you said you wanted.
You'll probably find that you don't need 4Gb of RAM at the moment (32 bit operating systems can only address 3.5Gb or so anyway), but it won't hurt. 64 Bit operating systems can make use of it however, so it really depends whther you get Vista 64 installed on the machine. I'd say get it anyway (the RAM, not Vista), but it depends on whether you're sacrificing something else that might be more useful (like extra HDD space).
Stick with Intel CPU's as they are the best of the bunch at the moment. I built nothing but AMD machines for 10 years, but whilst their CPU's are excellent value for money, the Intel equivalents are simply faster and better (unfortunately

). I've just put a Q6600 in my machine and it's pretty special, though the dual cores are also excellent.
If you want some advice on a spec, post it here and I'm sure everyone else will be happy to chip in with some opinions.