5 card draw

To warm up for hold'em, I sometimes play a round of 5 card draw.

Now my question: If I hold a pair and a high card, is it better to draw 3 cards and to hope for trips, or is it better to draw only 2 cards and hope for trips or two pair?

If I would suggest, 2 pair is high enough to win, where are my chances to improve the hand higher?