Currently I have an XD Tactical in .40 and I think it is super, though I carrry a H&K compact in a 9mm. The 2 biggest advantages to the 9mm were cost for shooting, and the larger magazine capacity. However, now the XD comes in a compact 45 that will take a 13 round magazine, and one in the chamber. Kinda hard to beat there. there are alot of people out there that willtell you to buy the .45 for self defense, it has more stopping power....etc. I used to be a part of this school of thought. But think of it this way, go stand in front of me, and let me plug a couple of 9mm rounds in your hide, and see it that doesn't put you down. IMHO, buy the XD in a 40. Costs a hair more to shoot than the 9mm, gives you just a little more gas than the 9mm, and genereally not as $$ to shoot as the .45. I suggest that you stay away from the .45 GAP simply because I don't consider that to be a walmart gun, meaning, that you can't always go to walmart and find ammo for it. Ihave foud that the GAP ammo can be somewhat hard to find, and when you do, it is generally even more expensive than the standard .45 Auto.

Since you say that you are going to take it to the range, and for self defense, buy the full size gun, however, if you are going to get a permit to carry, then look into their compact or subcompact models. Whatever you decide to get in an XD, you will, or I expect you wil be very happy with it.

Good luck to you.