this has got to be the most asked q on here, your best bet is
1) do a search on here for other peoples views
2) get down to your local shop/site or to a tournie and look at markers, ask people if you can try theirs, see how they balance, how they fire etc.... and see what you like
asking what you should get will only usually result in people recommending what they own themselves, when really its all down to personall choice......ive owned a few markers in the last 10 years and came back to using a highly modified version of the first semi i owned!
also at the moment is a great time to buy 2nd hand, even better in a few weeks, once the campaign cup is over there will be loads of cheap gear about