My weapon of choice is the CA CQB M4 with a Marui Glock 17 sidearm. I've got two or three hi-caps for the M4 that I only use for day games and 4 midcaps that I stick to for night games. The Glock, being my last resort in most cases, only has the two mags that come with the gun but it's really fun to use.
I've nicknamed the M4 the facemasher, in remembrance of some poor sod that I shot as he was coming down the stairs at the far end of the hallway whilst neglecting the unwritten rule of keeping your mouth firmly closed. As he walked past he said "You can have these back" and spat out a couple of rounds. I just love that gun. In all the time I've used it, even on a woodland game when it was pissing it down, which took out two of my friends' guns, it kept performing.
As for carrying the gear, I only use a tactical vest with 8 mag pouches and several other pockets which end up getting used for maps, mission briefings, glock mags, grenades and the odd mars bar or two.
Be aware if you plan on renting a gun for the day though, as in my experiences with people using them has been less than 100%. To give an example our squad of 5, in a team of around 60, was pinned down in the final minutes of a building defense. Three were on separate windows picking off the people using the stairs into the fire exit and the guy with the rent gun and myself were covering the door. He crossed the doorway, span to face the windows and threw himself against the wall before a volley of shots pinged off the broken light fitting. We were just about to lean round the corner when his AK literally fell apart as he held it, leaving me to deal with an m249 mounted on a windowsill facing the door and the entirety of the opposing team that were coming up the stairs.
I think he changed guns two or three times over the course of the day, settling on a G36.