Running a Athlon 2800 on me current box with a 128mb Gf4 Ti 4800 SE n 512mb DDR400 - can hit well over 300 mark no probs yet I still limit @ 73/125 (toggler)
- Got a K7-2600 with a 128mb Gf4 Fx5200, 1Gb DDR400 and 280GB HD total on its way… tommorow! 
Some advice for ya tho m8 when your computer has arrived and setup. Probably more than likely be better of picking a decent OS rather than the bundled XP Home they give ya with it I bet. XP Pro or 2K tbh. Format up straight away and clean up any shite, tweak some bits and peices for general performance (www.tweakxp.net) and remove IE/Outlook
Use Firebird and Thunderbird tbh… Update Direct X, Find drivers thats stable and runs decently (ask around on Forums for yer card and games) THEN consider rattling on all teh shit, eg, games, movies whatever basically. Make a quick fix point if its XP so any troubles you can just resort back to the first setup with everything clean installed and known to be working. Just what I would do and going to do, again. :>