I do knuckle push-ups out of habit, I'm quite a light guy so I can do loads of regular ones.
And yeah, if you can afford it get a punchbag- they're great. Good for stress too! Tho mine fell off the wall (bringing most of the wall down with it) a week ago, and I rele need to get it back up
grrrr ah well.
Oh yeah, and the wrist thing is very important. SHould you get in a fight the last thing you want to do it hit a guy and feel your wrist buckle. I dont know what kind of fighting u do, but for muay thai u wear bandages or wrist guards- and I'd strongly recomend them for punchbags.
All you do with the bandage is cut a hole in one end, wrap it round your wrist and hand (starting with the hole-less end) and, when you run out of bandage, put your thumb through the hole to finish it off. There, nice and cheap, and it'll be worth it.
I'd also like to suggest that you start with gloves, but then move onto just bandages, cos if your doing this to be ready incase of a fight, you'll need to be able to deal with hitting things. If you've never experienced hitting something with bare knuckles it can be quite a shock, my knuckles bled the first time I did it, but you build up a resistance after a while.
I'd also like to suggest weighted punches, it just makes you a bit quicker and improves the amount of force you put into the punches.
I'm mainly self taught, so I'm just saying what has worked for me- I do this stuff cos I enjoy it. Its more of a hobby than for fitness.
