Invariably, whenever you go to a 3-day music festival, people are going to ask you, "Who'd you like best?"
This is a difficult question to answer objectively, because there are a number of factors at play. First and foremost, bands you like before you've ever even seen them live will ultimately have the advantage. If that's equal, then you have to take into consideration whether you're seeing a band for the first time or for the 6th time. Then, of course, there are always outside factors at play: weather, crowd, temperature, position relative to the band (being close to the stage will always amp up ones enjoyment of a live show), the day of the festival (one tends to be in better spirits on Day 1 vs. Day 3).
For instance, I've seen Pearl Jam six times now - including Lollapalooza - and they were a major reason for my wanting to go to this particular festival this particular year. And no matter how many times I see them, no matter what kind of set they play, like Caitlin said, "They're always fun." That being said, I have Pearl Jam's show - likewise the final show of the festival - ranked 5th on the list of bands I'd seen; mostly because of the crowd being quite dickish (a point I'll save for a later review).
On Friday and Saturday, there were competing "Headlining" acts that played at the same time, for the same length of time (90 minutes, 30 minutes more than anyone else at the fesival, save Pearl Jam which had two full hours). I managed to be at the 1-a stage each and every night, so presumably I was surrounded by the larger of the two crowds on the first two nights, which would lead me to believe that these headliners were the more popular of the headlining acts. Including Pearl Jam, I have all three headliners I saw in my Top 5, which goes to show that length of performance had a lot to do with my ranking system.
Here's my top 5 in order of best to fifth:
1. Muse (Day 2 Headliner)
2. The Roots
3. Daft Punk (Day 1 Headliner)
4. LCD Soundsystem
5. Pearl Jam
Really, that list is deceiving because The Roots put on an absolutely mind-blowing performance and the only reason why they weren't Number 1 is because during the Muse concert I was in the front row on the right side of the stage, while during the Roots I was in the middle of the pack. Daft Punk is also pretty close to being my favorite, but I had to dock them because I didn't have any drugs in my system. With a light show like that, with the crowd surging and dancing in unison, with them playing all of their most popular songs in an intricate massive blob of a medley for up to 40 minutes straight without a break, my enjoyment of the show could've only been enhanced if I was tripping balls. A little LSD goes a long way, but otherwise they did fine. LCD Soundsystem ranked up there because they put on a supercharged show and never let the foot up off our necks; plus, I was pretty damn close to the stage here too.
The rest of the sets I saw, in order, are:
6. Kings of Leon
7. My Morning Jacket
8. Electric Six
9. Polyphonic Spree
10. Satellite Party
11. Smoosh
12. Blonde Redhead
13. The Yeah Yeah Yeahs
14. Amy Winehouse
In reverse order, I'll give snippets of my feelings about each. During the Amy Winehouse show, it was the middle of day 3 and I sat through the entire performance because I was tired and didn't feel like making my way through a dense crowd. The Yeah Yeah Yeahs played right before Muse, it was crowded, and I was way off to the right, making visibility a huge problem. Plus, I'm not familiar with their last couple albums, so I didn't know many of their songs. Blonde Redhead I was right up front, but I don't know them very well either. Smoosh really only played a 30 minute set, so that hurt 'em. Satellite Party was awesome, but didn't cover the Jane's Addiction songs I wanted; plus I was too concerned with getting a good spot at the LCD Soundsystem stage to stick around for the whole thing. The Polyphonic Spree was a mindfuck, but I don't think their performances are tailored for festivals. I'd like to see them in a more intimate setting where they can really branch out for a couple hours. Electric Six was high entertainment in the middle of the day, but had a lot of better bands to contend with. My Morning Jacket played pretty much like I expected, but they don't sound too different than the live album I have of theirs. And the Kings of Leon rocked, but they didn't necessarily blow me away; plus, they didn't play my favorite song of theirs, "Soft".
So, in conclusion, I'm gonna say Muse was my favorite, but I'm not discounting The Roots by any stretch of the imagination