Whatever you do remember that if you stick with the same size than all equipment you buy (cues, shafts, protectors) will be interchangeable, which means less money spending for you.
Most major retailers can re-pin a cue for a small fee. Also, most custom cue makers can use a pin that you request. So find a brand of cues that you would like to get in the future and then if you find something else than get it and have it re-pinned. I personally have all my equipment as a 3/8-10.