I grind so much it's unbelievable. Literally, between gym leaders I'm grinding three or four levels each time. I suppose it's harder when you have a full team, but I want to keep them at equal level and it just helps things when in battle to have a number of strong Pokemon.
I'm about to head for the Pokemon League, since I beat Clair yesterday (and the Kimono girls, and caught Lugia) but I don't want to be underlevelled as serious, important battles scare me a little. ^^;; So I'm grinding my entire team to about Lv. 45-50 before I try it. I'm using Ice Cave as a grinding hotspot, because while Swinub are stingy on the Exp, the Golbat, Jynx and Delibird are pretty good. I got my team from Lv. 41 to 43 in about an hour and a half.