Since I live in the Bay Area, I am an connoisseur of record stores (Amoeba, Rasputin, Tower - RIP) and Zia pretty well fits the bill for everything I look for in a music store, except for price. I know a lot of people have commented on how inexpensive Zia is, but that's probably because they're used to getting ripped off big time at Borders or Barnes & Noble for actual physical manifestations of music memorabilia - but as far as I'm concerned this place is almost expensive next to say, Amoeba Music.
But I digress, Zia does have a nice selection of used and new CDs and some vinyl. It's not a huge store so the chances of finding something extremely rare are pretty slim, but every once and awhile I was surprised at the little gems I found shopping there. They have a decent section of gag gift-type things and other merchandise. There are a few listening stations along the back wall featuring mostly new music, but also local acts, which I think it's pretty awesome. They have a small in stage in the back for in-store performances, though I was never lucky enough to catch one. Staff members are nice, but not overly effusive with helping you (which is a-ok in my book). They're also open late every night of the week which is a blessing, since most everything off the strip closes pretty early for city-dwellers.