You might not want to shoot the same thing at a deer as you do a bear. Killing deer is very easy. Over killing them destroys meat. Consider the range you want to shoot at. If you're under 200 yards, a normally loaded 30-06 is probably too much for a deer... unless you like hamburger -- or your shot is perfect.... so you would want a lighter load and a smaller bullet.
The title of this thread should be: "Looking-for-a-good-all-around-Hunting-Cartridge". Absolutely no offence intended -- but with that question, your research becomes easier. If you learn about sectional density of bullets and how it relates to velocity, you'll come up with a suitable cartridge -- and then you just buy a decent gun that shoots it. There is no all around perfect answer, but you should understand why the compromises are compromises. Personally, I settled on a 6.5 Swede. The higher sectional density mid-calibers like 6.5mm and 260, 270 etc are very nice to shoot (low recoil and flat to 300 yards) and very effective. They can really do a lot -- from varmints with a light bullet to a sweet shooting 2700fps deer bullet... to a big dead moose. They ain't for killing big things out past 300 yard though...
Experienced shooters may like the 30-06 (especially hand loaders), but they are nasty to shoot compared to a 270 or so.
Don't forget to consider the size off the hole on the other side of the deer.