Depends how much you are willing to pay for one. There are a huge market of good quality amps out there. IMO i like the old school amps much better than the amps now a days. They just make them too vicous looking and they just make them so big to where you cant find room to mount them anywhere unless you have a SUV or something. Here's quite a few good brands out there that will rock your JL's.

-fosgate (the black dsm models made back in the mid 90's)
-phoneix gold
-zapco
-mmats
-soundstream (old school models)
-US amps
-Orion Red (HCCA series)
There's alot of other good amps but these are the one's that I would prefer. These amps are quite expensive, you're pretty much paying $1-2 per watt.