Eric,
Some simply enjoy shooting heavier bows and if you are healthy and take your time, there is no reason you can't shoot a heavier bow. Personally, I have increased from 55# holding weight in June of 2010 to 80#+ today and I can shoot them accurately, without shortdrawing, excessive strain or shaking. I have a 90# bow I currently use for exercises and have no problem shooting or hoding that bow at full draw for 10 second counts when exercising. To me there is really nothing like a heavy arrow screaming to it's target.
Here is the problem, you just can't pick up a heavy bow and yank that sucker back if you are used to shooting 45#s. You will need to work your way into the heavier stuff. Also you should develop an exercise regimen to not only work up to the heavier bows but also to maintain the ability to shoot them. You can't shoot the heavier weights once a week and expect to shoot them consitently. If you would like to hear about the exercises I use just shoot me a PM and I will let you know what worked for me.
As Rob mentioned above, you also have to keep "Actual hunting situations" in mind. Can you pull the heavier bow back in a hunting situation and it pays to practice shooting in simulated hunting situations. It does make a difference so also, keep this in mind. One thing I noticed was it will be harder to shoot the heavier bows when you have been sitting in a stand in cold weather for a few hours. You can over come this some by drawing the bow a couple times every hour or so, or if you hold on to some of your lighter weight bows as you work up to the heavier weights, use one of those as it gets colder. This is what I plan to do in 2012.
Just remember, where you stick them is more important than how heavy your bow or your arrow is. As has been stated 50# is plenty to kill deer, bear, hogs, etc. So it really comes down to what you want to do personally. If you decide to shoot heavier here is some advice:
1) Take it slow and listen to your body, at some point everyone hits a wall.
2) Don't ignore any signs of a bow being too heavy, an injury is much harder to recover from that building strength.
3) Don't me or anyone else tell you what you
can or
can't do. Make your own decisions based on what you research and gut feeling. (I did not do this and somewhat regret it)
Heavy bows are not for everyone and I still enjoy shooting my 56# Shelton(It sure is easy to shoot after going up in weight) For me it isn't some macho crap or any kind of "I am better because I can...." BS. I just enjoy it! Plus in many cases the used bows are cheaper!
Good luck to you no matter what you decide is right for you and the main point to keep in mind is to have fun!!!!!!!!