Will Whole Foods Market ever replace Giant Eagle as my regular grocery store? No way! I'm a cheap grad student!
However, I was pleasantly surprised when I walked in for the first time, out of boredom/curiosity. I only bothered checking out the produce. Of course, the regular prices are more expensive than geagle and probably also Trader Joe's, but not totally absurd. For example: Whole Foods organic apples -- $1.99/lb. Giant Eagle conventional apples -- $1.69/lb. I'm ok with paying $0.30/lb more for those organic apples! They also had some local conventional fruits on sale for cheap when I went. Overall, a decent place to shop. You can probably find at least a few things worth getting here.
Update: After a few more visits, I've found that a surprising number of items are cheaper or the same price at Whole Foods compared to Giant Eagle, including: pecans, WF milk, and semi-sweet chocolate chips.