I play 400NL and I still think its profitable to limp/call raises from EP with low pairs. The nice thing is that against full stacks, you are getting 1:20 odds, so you dont have to take as large a % of their stack to be +EV. Conversely, against shorter stacks where you might be getting only 1:10 or 1:8, I still think it works out to be +EV because 1/2 stacked or lower usually means a bad player who will be willing to dump off with tptk or high overpairs.

Acutally, I play JJ and below from EP for the set, usually. Sometimes if the flop comes out all rags and I have say, second PP or PP over the board (like TT or 77 on a 862 board) Ill lead into the PFR to see if hes really got an overpair or just missed high cards.

I open 88+ from mid to late position at hight stakes, THOUGH ONLY against open limpers who I deem to be most probably set camping. (I also raise suited connectors under this philosophy as well). I figure against an open limper, the only hands I want to go to huge showdowns with are hands that will beat low sets.

Similarily, I try not to play for stacks with a low set against a good player showing alot of postflop agression. Using pot control here is key.

Obiviously big pairs AA-QQ lose a bunch of value as stakes increase. I think good play with these is very dependent on your read of your opponents style and general skill level. I try to pick players on the table that I will play for 1/2 stacks with with AA or KK unimproved. Obviously I'm not looking to get this much in against a good player who limp-called my PFR.

Also, one shouldnt forget the power of floating against good players from the c/o or button after calling their raise with a low pp. This can be very profitable against the standard taggs at 1/2 and higher.