How about the one on the left? Starts at $750 and the specs look okay and it even includes the Core i7 920 and Vista Professional 64bit. However, the Radeon 4350 video card they have included in the price is worthy of a "WTF". It would bump up the price a little, but using the Radeon 4850, or at least the Radeon 4670 would be better. However, the 4850 would be the better option to utalize more of that nice Core i7.
http://www.dell.com/us/en/home/desktops/desktop-studioxps-435mt/pd.aspx?refid=desktop-studioxps-435mt&s=dhs&cs=19
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That's just one choice and there are numerous other computer dealers for pre-built systems. If she wont use it for more heavy gaming and stuff like video editing then the i7 is probably going to be more of a waste of money since it's high end (unless there are any future upgrades planned as prices of GPU's and RAM go down). If she waits, Intel will be bringing out the mainstream Core i5 eventually. Heck, current intel Core 2 Duo/Quad are good too.
I haven't really followed AMD so somebody else would have to recommend AMD systems.
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Here's one from HP using a Core 2 Quad 9400 for $769. The graphics are a little weak with the Radeon 4650, but the Nvidie 9800gt and Radeon 4850 are also available.
