I prefer ultimate-guitar for generic stuff, but depending on what you play often specific tab sites ar the best.
www.spatchpatch.com for Dispatch tabs
www.dmbtabs.com for Dave
there's also a really good ben harper fan site with great tabs, but I dont know the site offhand.
I started using olga when I first started playing, but I dont like it anymore. new stuff doesn't show up quick enough and old stuff isn't very accurate (i.e. they know their G-Am-F, but not specific voicings or fills a lot of the time)