YouTube User 331Erock covers "Dragon Soul" (with Dragon Force's "Through the Fire and Flames" thrown in for good measure).
Gino Padilla performs this "official" Philippines' dub version of "Cha La Head Cha La".
"Official" FUNimation dub of "Romantic Ageru Yo" performed by (I think) Laura Bailey.
ANIME THAT JAZZ covers "Romantic Ageru Yo", instrumentally.
An awesome compilation of YouTube covers of "DAN DAN Kokoro Hikareteku". Too many credits to list here, just click the "watch on YouTube" link.
ZARD's "cover" of "DAN DAN Kokoro Hikareteku". Interesting story, ZARD vocalist Izumi Sakai originally wrote the track for FIELD OF VIEW (the version used as DBGT's opening theme). So while this is technically a cover, it is, in my view, the true version.
A remix of the Bruce Faulconer Perfect Cell theme, by an unknown artist. (Yes, I just posted a dub music cover. Don't have a heart attack on me bro, it's actually really awesome.)
Know of some other awesome Dragon Ball song covers? Lemme know at firstname.lastname@example.org, so I can post them in part 2!