Whatever you get, base it around an Athlon64 3700 or 3800. Two of AMD's most overclockable chips.
With stock cooling and voltage you can get FX55 speeds and with some tweaking (still with stock cooler) you can get FX57 speeds, with the right RAM (Mushkin high-end RAM is generally the best).
For a gfx card, the 7800GT represents fantastic performance for a reasonable price. A 6800 Ultra is also a hot pick, for slightly less £££.
If Alienware can provide a system based on those components, and you feel it's a good deal then go for it. At least purchasing a whole system, if it screws up you can just phone 'em and get 'em to sort it out. If you build your own, you fix your own.
With stock cooling and voltage you can get FX55 speeds and with some tweaking (still with stock cooler) you can get FX57 speeds, with the right RAM (Mushkin high-end RAM is generally the best).
For a gfx card, the 7800GT represents fantastic performance for a reasonable price. A 6800 Ultra is also a hot pick, for slightly less £££.
If Alienware can provide a system based on those components, and you feel it's a good deal then go for it. At least purchasing a whole system, if it screws up you can just phone 'em and get 'em to sort it out. If you build your own, you fix your own.