Get out in the woods as much as you can and begin to learn the habits and areas liked best by the deer in the area you are going to hunt, get to know the land, the bedding areas the feeding areas and where they travel. In the long run, knowing and understanding the Whitetail, (assuming that is what you are going to hunt) is more important than what caliber or make of rifle you shoot.

Since you do have friends that hunt deer, I would suggest that you do speak to them. Find out what caliber rifles they own and possibly get them to allow you to fire them at a range, preferably a couple of different ones the same day. Do a bit of research on the web sites buckmaster posted so you have a bit of background then try several of the different rifles available. Time is on your side, you have plenty of time to make a selection now before next season and do some practice with it and become proficient at ranges you expect to be shooting at.

You don't mention anywhere, where you are from. Since you already own several shotguns, you might consider using one of them with slugs. The slugs that have been developed over the past 20 years are deadly accurate out to 100 yards if you have a shotgun capable of shooting them proficiently. You might consider a slug barrell for your favorite shotgun as an alternative or as a backup.

Don't forget to consider using a bow, bow shooting is a challenge in and of itself and you can have hours of fun just shooting a bow in the backyard or at a 3D range while learning the basics.