With a decent pair of in-ear noise canceling head phones, any EQ is useless..
I went out and bought the Skull Candy Holua series head phones, at a steep $129.99 CDN
LINK
The sound quality (to me) actually LOWERS when I use the (iPhone 3GS in my case) built in EQ on any setting other than none. If you want to use cheap less than $50 head phones, use Loudness IMO.