Earl is ace - just hope for good weather as it's cold, north facing, and tends to stay damp. I've been on 4 occasions and only managed to climb once
. Tonnes of good problems have already been mentioned: Earl is very good for slightly bold V3ish stuff - slabby aretes et al. I'd also add Hanging Groove and Trick Arete to the list. A warning re the latter though, if you're finding it hard, do not perservere. That problem utterly destroys your skin, especially on a sweaty day!
Brimham: is superb though it will probably seem less so on a Bank Holiday Weekend (especially now the parking is £4.50). Very confusing to the unfamiliar even with the Yorks Grit Bouldering guide - don't be afraid to ask for directions. Though as pointed out you'll have a lot of fun just trying everything and it's one of those places where just being there can feel special - finding a quiet spot and just soaking up the prehistoric ambience. Personal favourites include:
Pommel (V4), Anchor (V7 - soft if your are tall), Black Dog Arete (the front of an arete on a buttress to the left of Pommel), Acme Wall (V3), Happy Days (V4-5ish), Pair in a Cubicle (V6), Whiskey Galore (V6), V3/4 overhanging arete near Lovers Leap.......
Other good places - Slipstones (possibly a bit far north) is fantastic with a good mix of bouldering and microroutes. There's a free pdf topo at yorkshiregrit.com too. If you find Earl is wet and can't be bothered to venture too much further, you could do a lot worse than Shipley Glen. Lots of good slabs and aretes at the far end: Millstone (V5), Manson's Wall (V5), Vim (V2), Red Baron (V7); and lots of microroutes nearer the pub. Just watch out for broken glass and wandering "yooths".