Hmmm.....Not one really stand out for me, but I guess Lollapalooza a few years back w/ Jane's Addiction, Audioslave, Incubus, Queens of the Stoned Age, Jurassic 5, and Papa Roach. Or Tom Petty show was pretty cool, 311 usually puts on a good show the 2-3 times I've seen them. And even though I was dissapointed at both of these tours the Anger Management Tour and Projekt Revoultion they were pretty tight just for who was on'em. Anger Management: Eminem, D12, Xzibit, Ludacris, X-Ecutioners, etc. and Projekt: Snoop Dogg, Korn, Linkin Park, Ghostface, M.O.P. etc.
But the best Tech showing I've ever seen? Would have to be at the Puff Puff Pass Tour w/ Snoop Dogg, Kurupt, The Liks, Short Khop...can't remember who else. But I tell ya, it was when Tech first dropped Anghellic and he opened the show and people were going nuts. All I could think of was Snoop sittin back there wonderin..."Who the fuck is this on stage?"