I'ved used the following:
Traffic-out - the traffic was good and productive. It was a little slow in the delivery, but well worth it.
Choker - Now, I've run some careful experiments with choker traffic. I've tried it on some galleries. Galleries that would normally convert at 1:300 with standard tgp traffic, would convert at 1:5000 with choker traffic. I still turned a profit but not enough to keep me interested in trying it
FPCTraffic - Ravo is pretty reliable traffic and pretty good cheap feeder traffic. You can buy a variety of traffic from clicked North American only, etc, etc, etc.
If you're looking for traffic to build a hub, tgp, or linklist, I'd probably recommend going directly to some established tgps and think about buying links with them.