You said in the first post you enjoy pulling things apart - i would definitely go a machine similar to what narf said - one that needs a good clean and maybe a few mechanical adjustments, or a couple of switches no working. That way you really learn about what makes these things tick.
My 1st was a non working (it turned on but wouldn't start) Flash, i had no idea but with the help of the guys on here i got it going. I really enjoyed the challenge of making something work that hadn't been, but it depends on what sort of person you are, if you get easily frustrated or are impatient, this may not be the way to go.
Another title that i personally reckon is great bang for buck is Roadshow, sure the heads are a bit fiddly to pull apart, clean and adjust, but i loved getting mine all cleaned up and going and it is one of my most played machines.
