PC Vista-Ready?

Hello, I built a PC at Christmas time 2005, so only a few months ago. I am wondering if, without much lag, slow response time, and what-not, my PC is capable of running Windows Vista (maybe not FULLY featured(AERO-GLASS turned off))? Here are my PC Specs:
Pentium 4 640 3.2 GHz EM64T 2mb L2 cache HT enabled
1 Gigabyte RAM
I have built in graphics at the moment but I AM going to get a PCI video card, either soon, or right around Vista's relase (to make sure it is fully capable of working well) and maybe then I COULD run Vista with some graphical goddies turned on.
200 Gigabyte Hard Drive
Yea, thats the basic specs if you need any more details, just post the queston and I will answer it as soon as I see it.
Thanks!

EDIT: My Motherboard is: ECS RS400-A with built in ATI Radeon XPRESS 200. I was wondering if these graphics are good enough to even run Vista AT ALL (under classic or XP mode) most likely Classic if it is available. Thanks for any help

It will fine as far as the bit I know about Vista but ditch the OnBoard graphics like you said. Get the best graphics card you can. It should run fine otherwise.

Thanks for the quick reply like that! Yea, thanks for the suggestion I'll do that fairly soon! All right then! Thanks again! Do you think with the PCI graphics card I could be able to run ALL the Eye-Candy elements? And use Vista's FULL graphical power?