I am working on a side project for one of my managers here at work. I need personal opinions on recommendations for the different parts needed for a complete build. What products do you recommend and why? He is looking for the best bang for the buck, basically. Any help I can get on this will be greatly appreciated. Thanks

Build what ? Workstation or Server ? To accomplish what tasks ? ...

workstation. for personal home use. the computer that he has now is about 10 yrs old. hes debating whether to do new build or just upgrade. i told him new build bc it will be easier to upgrade down the line. the usage is for playing games, data processing, internet, those sorts of things. nothing major.

Athlon 64 X2 CPU

Asus or MSI boards give you pretty good quality and are generally priced pretty low.

160-500GB HDD (less than 160 or over 500 costs more per GB, 160-500 is pretty consistant)

Probably give him a decent integrated graphics unless he'll be paying "serious" games, which I doubt he would be if he's working with a 10yo system and thinking about just upgrading it. You can always put in a dedicated card after the fact if his games don't perform well enough. before I could recomend a video card I'd need to know the types of games you're talking about, but generally a geforce 8500 is a good all-around card.

Basic DVD burner and a card reader.

If you're going for vista I'd say 2Gb of PC2-6400 since it's only a few dollars more than 5300, 1gb if he'll be running XP or you're trying to keep the price way down.

If you're doing a monitor too 19's are usually the best value. They're only a couple bucks more than 17's and less than 15's.

This site has information on performance-per-dollar on CPU's and graphics cards, it's measured in gaming benchmarks but you can get a good sense of the value in other applications from there.
http://www.yougamers.com/hardware/stats/3dmark06/priceandperformance/