Palpitoad's pretty good imo - grass isn't a type that appears very often (I think?)

I decided to use Serperior but also Virizion.

Palpitoad's final evolution, Seismitoad, is one of the best new water types that you can use on black/white. Not only does it have a very high HP value, it has balanced stats as well.

It's extremely weak to Grass though, given it's Water/Ground pairing, so pokemon like Leavanny, Simisage or Serperior can destroy it in one hit. The other water options that you have aren't much better, maybe except for Basculin, if you want a hard hitter Water type, but with worst defensive stats than Seismitoad.

There have been many in previous generations though.

i thought the early part of the game was rampant with grass types (especially around pinwheel forest), but not so much as the game progresses

(probably because my team wasn't so good against grass, so they kept throwing them at me)

Well in the post game battles, like Morimoto, Bianca and many of the Nimbasa Dome trainers like to use Simisage a lot. Also, I've seen Gothitelle's using Energy Ball as well.

When I saw a chess Pokemon I was ecstatic! I knew Pawniard would evolve into a Bishop like Pokemon.

sigh went yesterday to buy black and white but i coudnt find it. i have two options or i wait for viring to get it which will take time considering they get ps3 games 1,2,3 weeks late(they represent the bulk of their software sales) so im expecting around a month for bw. unless i get the pirated copy. 

Pretty sure everything i have can learn Rock Smash, which'll make it fun conquering the Normal Gym.

But i still have to punt my whole team about 5-6 levels each to get there...

Trust me, you'll want a Fightning type to get advantage of the STAB. 

The Normal gym is harder than you think, for such an early stage gym.