Lots of options out there. The Velvets are popular on J-Customs. JEM Single is popular as well. Without knowing what kind of music you plan to play or what kind of playing you plan to do with the middle pickup, people will not reply too specifically. I got a ProTrack because I wanted something loudish with a small-ish tone difference with the ToneZone and the
PAF PRO. I haven't wired it up yet though, because my soldering iron is as big as a rocket.