If you intend to play raster games, make sure not to get a vector cab. No matter what you do, you cannot play raster games on a vector monitor. If you liked the old vector games, then do what the guy above said, with vectormame.
If you can't tell which games are vector or raster by the name, some tips: If it has a B&W monitor, it is a good bet it is vector (though not always). Also some color screens were vector as well. Another good point is if it is from the 80's or before and has analogue controls, it may also be a vector cab (as before, not always). One almost sure fire way to tell just by looking at the screen would be to look at the burn in pattern. If you see nice diagonal lines in the burn in, or the text/numbers in the burn in look "liney" then it is most likely vector, on the other hand, if the burn in is of distinct area patterns (whole blocks of the screen) and the text/number burn in looks blocky, it is prolly a raster display.