Favorite Concert: Probably the Streetlight Manifesto one I just went to
Biggest Concert: Little Stevens Underground Garage Festival. something like 22,000 people were there
Most Expensive: Would have been Lollapalooza (got canceled grr)
Least Favorite: some stupid free one.

Favorite: Jean-Michel Jarre : Destination Docklands 9.8.1988
Biggest: Jean-Michel Jarre : Oxygen in Moscow 6.9.1997 (3,5 million people)
Most Expensive: maybe the first one, but from what I've paid, Cracow Klezmer Band concert in Helsinki 31.3.2004. About 20 euros.
Least Favorite: Maybe some of those billysillythings I saw in the lower stage.

best - leeds
biggest - leeds
most expensive - leeds 2005, £137 this year, ouch!
least favourite - meh, cant pick.

Best: Eric Lapointe in Sept-Iles
Biggest: Gregory Charles at the Centre Bell (7 000 people)
Most expensive: Gregory Charles ($60)
Least favourite: Yelo Molo

Best: Jump, Little Children @ The Georgia Theatre Feb. 2002
Biggest: The White Stripes free show
Most Expensive: U2 $54
Least: Some local band.

Best: Kutless
Biggest: Newsboys

I have a lot that i planned on going to but wound up not being able to. Two against me! concerts in Florida, a cancelled streetlight manifesto concert, and I lost my ride to a "my chemical romance concert.
edit: and a blink 182 concert, but that wasn't too much of a lose. I just wanted to go because it was a concert and I liked the song 'Dammit'.

I dont know how many people were at each and I cant pick favorites out of all I've been to so I'll just list who I've seen:

Lynyrd Skynyrd
Van Halen
Boston
Journey
Yngwie Malmsteen
Steve Vai
Queensyrche
Scorpions

Favorite: Thin Lizzy, Satriani, Deep Purple, all in one show
Biggest: ^^^^
Most expensive: $60 for Pixies, friend had passes for Deep Purple show, so it was free
Least Favorite: Schools variety show? Everclear in the 7th grade?

Favourite: Very hard to pick between Oasis for the atmosphere, Keane for the amazing performance, and Muse because, well... they're Muse. Actually it would definitely be Muse if the sound system wasnt a little shoddy.
Biggest: Oasis and Powderfinger at Livid festival. Massive.
Most expensive: Coldplay, I think, bout $80.
Least favourite: The warm-up band for Franz Ferdinand. Boy did they suck.

Favorite: Live 105's BFD (local radio festival) in 2000. Stone Temple Pilots were the headliners, right after Scott Weiland got out of Jail.
Biggest: BFD in 2000 or 2001, probably around 25,000
Most Expensive: Probably Family Values Tour in 2001, something like $35.
Least Favorite: Some band at a house party or something like that.

Favorite: Curiosa (SO many GREAT bands)
Biggest: Probably HFStival last year, when The Cure played
Most Expensive: Definately Curiosa
Least Favorite: The local shows around here make me want to puke...

Favorite Concert: Streetlight Manifesto w/ MU330 and Voodoo Glow Skulls (it was so awesome...)
Biggest Concert: Warped Tour 04
Most Expensive: ^
Least Favorite: Acapella group called Inside Out...