I myself use the Novation impulse 25. It fits in the Magma riot dj xl bag with laptop, pad controller, AI , headphones, cables, other stuff.
It's a bit on the big side , but with the bag, everything fits easily and is easily transportable.
I also used to have the Akai LPK25, but that was too crapy small to really fulfil my needs
If you don't mind crappy keybed, small, but responsive , it's ok. You could also get the mpk mini with pads.
They also have the mkII
Akai max 25 looks good as well
You could also go for an as basic possible midi keyboard with 25 keys. Like the Keycontrol 25. Then buy seperate knobs/faders and pads. They come in handy packages as well.
Like the Akai LPD8, Ion has similar stuff.
Emu xboard is nice and small as well. With a lot of knobs.
Lots is down to preference.
A review page with a few more choices.
http://www.wirerealm.com/guides/best-25-key-midi-keyboard-controller