ak47 or grenade launcher is my bet for range L4D2, melee... chainsaw :P

umm and tips for the grenade launcher, user things like boomer bile or something to get alot all nice and close together, and for in close quarters or when there not near you, either use (in my opinion) a desert eagle, or a good melee weapon

Drawing them into a large group, always a good idea.

yup lol, and im fairly sure you know this already, but each assault rifle has different advantages

scar (tan one): largest magazine least damage
m16: medium magazine medium damage
AK47: smalled magazine highest damage

WEll for me any machine gun will do fine my fav melée weapon is the cricket bat (woot! Shaun of the dead style!) and the chainsaw. Why do I like the cricket bat? Well if all the players had one they can easly jump a wich NO LIE! me and my friends took a couple down with cricket bats it's pretty funny acualy and the chainsaw u can just walk up to her and kill her in a matter of secs X3 I also know a few tricks ;)

I was not aware that the cricket bat could be so effective. Thanks for the tip!

Well all melée weapons do the same damage, you should use pistils in close areas like rooms and hall ways beacause usualy zombies are comming from this way or the other and you can easly take them down with pistils (this is a good way to save amo for the big guns), another tip is if u stand right next to a smoker or charger they can't do any kind of damage only melée damage (they can't charge nor wrap you up) to kill a hunter if it's in a pounceing psition push it away then shoot it in the face. Stay in a group jokys and hunters usualy don't attack because they think twice. When u hear a joky stay in a small huddle and wait for it to come out once it attacks/apeares shoot it. If a tank apeares get to high grown and attack it from up there. If a big hord comes get into a corner and use melée weapon you will get damage but u will easly take the hord down.
If you want to heal quickly use a adrenaline then use the 1st aid kit to heal quickly

those are some tips I know

I prefer a shotgun, With a desert eagle for my short range. Long range I prefer that one sniper rifle in L4D2 that shoots pretty fast. I prefer pipebombs for the horde and mollitoves for the specials. Even the Tanks. If everyone throws a cocktail Tank has to walk through 4 fire pits.