Chances you need it...almost zero. Brymoore however is incorrect. Just a couple years ago a grizzly attacked and killed campers in Soda Butte Campground, MT just outside of Yellowstone. They were all sleeping in a tent, and multiple tents were attacked. A rifle and bear spray is probably more than enough, but either would be tough to use in a tent.
I have both a Glock 20 and a 329pd. I like both, but lean toward the Glock for most uses. When weight is a premium I tend to take the 329 as it is noticeably lighter. If it matters to you, the Glock is a great general purpose handgun that is fun to shoot the 99.9% of the time you are not backpacking. The 329 is not fun to shoot at all and generally sits in the safe most of the time. If I had to pick only one it would be the Glock.
Brymoore was right. Statistically, the tent attack is extremely unlikely to happen.
Likely a much better chance that a drunk naked co-ed will stumble into your tent than a bear.
If I'm packing a rifle, I skip the handgun.
