For me I love Shout/Pjanoo, blasting that over the surround sound is amazing. Also nearly all the Daft Punk mixes follow close behind. The mixes that I hate are the ones done by Grandmaster Flash, not sure if anyone likes them, but IMO they're terrible.

the grandmaster flash ones to me seemed a little boring, i really like Tears For Fears – “Shout” vs. Eric Prydz – “Pjanoo” mhmmm :]

Through the Grape Vine vs. Feel Good Inc.
&
Shout vs. Pjanoo
 
Both amazing. 
 
 http://thepiratebay.org/torrent/5205117/DJ_Hero_Complete_Rip_320_mp3
Enjoy kids

All of the Daft Punk mixes are great

" Through the Grape Vine vs. Feel Good Inc. & Shout vs. Pjanoo  Both amazing.    http://thepiratebay.org/torrent/5205117/DJ_Hero_Complete_Rip_320_mp3 Enjoy kids "

Robot Rock vs We will Rock you, but there are a lot more I love 
I hate the Rihanna vs Killers one, it just sounds really bad to me

I dont really hate  any of them actually, I like most of them. I think, sadly, the ones i have been most disappointed with were the David Guetta DLC mixes, because they didn't feel like Mash-ups to me, like the rest of the soundtrack(Sadly..because i payed for them -_- ).

I think my favorite mix is David Bowie/50 Cent,  or the Eric B and Rakim/ M.I.A mix.   Bowie/50 Cent is right in my wheel house...even though i strongly dislike 50, i dont mind him being torn apart by a DJ.   Same with M.I.A, don't really care for her rapping, but i love that mix. I was surprised by the quality of a lot of the mixes done in house, all of the music in the game sounded at least decent to me. Herbie Hancock/N.E.R.D deserves a honorable mention even though Grandmaster Flash is annoying, but i expected it when i heard he was gonna be in the game. LETS GO BABY LETS GOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO!

I'm a fan of most of the Daft Punk stuff (though the NASA mix is kinda dumb, in my opinion), Ice Ice Baby/Can't Touch This, Poison/Word Up!, and Juke Box Hero/DJ Hero (which I am officially changing to simply "DJ Hero"). Yes, I know, not many people like that last one, but I thought it did what it set out to do: turn a song about guitars into a song about turntables.
 
As for songs that I dislike, I'd have to go with Monkey Wrench/Sabotage and anything involving either Eminem or Rhianna.
 
But no matter what song I'm playing, I've found that the airhorn sample makes everything better.

The DJ Yoda stuff in my opinion is the most fun to play, especially the extra beat.

Tiesto VS Benny Benassi - Satisfaction VS Elements of Life  
 
I think this song is epic to play. Especially on Expert.

Megamix 2 by daft punk is pretty win not gonnna lie.  I like groundhog alot though.  But after hearing these new dlc's comming out for psn next week they are very sexualy arousing.