I just did a comparison of shopping at NewEgg and it seems that if I bought everything that the emachines offers, KM266, 512 PC2100, ATI Radeon 9700 Pro, ... it seems that i am over budget by about $100 to a total of $1130, from $999 for what e-machines offers. The Radeon Card puts me overbudget, i'm sure they're getting it for way less than advertised and the quality of the other components are questionable. Memory has sure gotten expensive since last year. If you wish to purchase the emachine, you better hope that they would at least use good quality components. On the other hand, if you build your machine you could debug your system much easier if a problem arises.
It's really up to you. If your parents are buying it, then I would go for the emachines (yes, even after all the horror stories i heard). But being a working person and knowing how quality is important, I would build it myself. I've bought one computer in the past from Circuit City (1995) and have had so many problems. But I have also built 3 systems since then, and I have had no problems, well possibly software (only because windows sucked).
Whatever you decide, i hope you know the consequences. It's either a trade-off between quality and quantity (age old rivals).
Good luck.
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<b>All the world's problems can be solved through COMMON SENSE<b>