Price is so arbitrary on these, I would agree with the statements made before about finding something you like. The nice thing about pins is that if you do your shopping well and are patient, you can usually pick one up for a great price and flip it if you don't like it...
For those who think Whirlwind isn't for kids, check my video out
http://www.youtube.com/watch?v=qruNqc0xfHM
The most I've paid for a pin was 1675 and I have only paid over 1000 for one:
Twilight Zone, Whirlwind,Pinbot, Bride of Pinbot, Black Knight, Black Knight 2000, Centaur, High speed
My first choice for a starter pin would be Whirlwind or Pinbot. Pinbot's go all the time for 600-1200. I think those pins(and other Williams pins from that era) really let you learn how to play pinball. Yeah they can be hard, but the rules are deep enought to be interesting, yet simple enough to follow while you are trying to figure out how to really play pinball.
BK2000, STTNG, TZ and games like that are amazing...but, if you don't know how to play, I think you spend too much time trying to figure out what to do on the playfield, without really ever learning how to use the flippers well, or nudge the machine properly.
On a side note, after moving my Whirlwind to the hospital, and playing TZ for a few weeks, I went back to play a few games of Whirlwind and doubled my high score... However, I still suck at TZ.
That's my .02 x 50