Certainly all good suggestions thus far, and I'm sure more will be forthcoming.
Having tried numerous types of muzzleloaders, I have found that I personally prefer the break-open, in-line models, using the 209 shotgun primer. Of course, that is very much a personal decision.
You will need to determine the caliber that best suits you (.50 seems to be the most popular, but there are several others also on the market.) Then you need to decide what type of ignition system and propellant you want to use (traditional black powder, a substitute powder, pellets, etc.) This is something that you can play around with after you've purchased your gun. Next, of course, what type of projectile (bullet) will you want (again, lots of time at the range, trying a variety of propellants, different charges and projectile combinations, will help you make the choice that works best for you and your gun, and give you a lot more confidence in your ability to take a deer with one clean shot.
I bow hunt, rifle hunt, and of course, black powder hunt, and by far my favorite weapon is the muzzleloader. I think you have a lot of exciting times in front of you and wish you the best.
As I'm sure you realize, rarely do we get a second shot with a muzzleloader (although I did once manage to re-load and take down a deer that I had completely missed with the first shot......that just doesn't factor in very often. Therefore, I would recommend that you not get too hung up on how quickly you can get the gun reloaded, but instead, you might want to consider how easy it will be to take down and clean properly once you are finished your hunt. Also, some propellants are less messy than others, but again, that is often another personal preference.
After you've made your decision and spent some time with your new gun, why not drop a post in here and let us know what you got, and how it's working out for you.
It isn't what happens to us, it is how we deal with it, that matters most.