Good question...I'm just going to add to Ioavva's list since she already named off several of mine too. Let me see if I can put it into words.
Manly behaviors for me would include (in no particular order here):
#1 Standing by your lady when she's standing up for herself. I'm a woman who can very adeptly take care of most situations, but there's just something comforting/sexy about knowing my man is right behind me if I need him.
#2 Looking at me like I'm the only other person in a crowded room.
#3 Quiet Confidence. You know...someone who can own a room, without saying a word. This is someone who holds himself up proudly, head up, looks people in the eye...not a braggard or a big mouth!
#4 Gently guiding your lady through a crowded room w/your hand on the small of her back.
#5 Standing up for me if necessary when I'm not even present. My H doesn't let ANYONE badmouth me.
#6 (goes w/#5) Praising your W when she's not even around. This is also something my H is constantly doing. I've heard from many friends how he brags about me, which is wonderful...now he just needs to let me in on it too LOL. But I do find this quality in him VERY appealing.
#7 Playing w/the family.
#8 Backing you up w/the kids and not making YOU look like the bad guy all the time.
Ok....now I'm drawing a blank, those were hard enough to come up with right now LOL.
Now...here's what I find to be jerkish behavior...
#1 Interrupting to correct me when I'm trying to explain something.
#2 Yelling/cursing in public!
#3 Self Deprication. I HATE it when a man consistently puts himself down!
#4 Treating others rudely....i.e. waitstaff. It was a deal breaker for me when dating if a guy treated a waiter/waitress rudely. Unecessary, uncalled for, tacky & rude!
#5 Not responding to e-mails.
#6 Assuming I should just know he loves me because he's still w/me!!!....put that one at the top of the list!
#7 Not backing you up as a parent w/the kids. If you have set out a consequence/punishment for something and it needs to happen....he needs to back you up on it (and vice-versa).
#8 Hearing him brag about himself all the time. You know...someone who is just wrapped up in how wonderful they are.
Hmmmm...I know I have more of each, but I'm a bit brain-dead right now.