ajwposh said he wanted strong on Vista and reasonably good at games. That to me doesn't say DX10! As far as DX10 is concerned... it's out, as Vista is out. DX10 cards are available now (nVidia only) but cost a lot. There are no DX10 only games available [or in fact officially announced]. There are some games that will have DX10 capabilities - Crysis, Flight Sim X and others. Halo 2 on PC will probably/most likely be a DX10 only game as all current information points to a Vista exclusive... on that one it's Microsoft's strange marketing decision perhaps assuming people will upgrade just to play Halo?

Yeah right :) By the time support for DX10 is widespread, the 1st generation of DX10 graphics cards will undoubtedly have been replaced with cheaper/better revisions.
As for PC's... if you want the best then buy a selection of bits and build it. If you want a good looking system that's well built, buy a Dell. Although HP also do some good machines (slightly cheaper than Dell perhaps) these days, I'd personally stick with a Dell.
Finally, always ring Dell to see what deals they can offer you. As the saying goes, if you don't ask you don't get! Just be sure to be clear on what you want, what prices are available on the web and what you're being offered - not all deals are great deals.