I've been meaning to do this for awhile, and I'll do it now since my videos are uploading to youtube for my second montage...whee.
First off, I'm going to give you my opinion on what guns rock, and why. I do not use the same equipment you see most people running around with, because I like being different, and I feel that if I can destroy the enemy even when they're all using FAMAS or AK-74u (which are, in my opinion, cheap as hell) that shows my skill a lot more than does using the usual guns you see the randoms using.
So, first things first...I differentiate a bunch between what I use for Core and HC, of course.
CorePrimary:
I have three guns that I love using. Firstly, I prefer the Spectre with fore-grip over any other SMG. It shreds people at CQB, has high enough accuracy that you can reliably hipfire if you're taken by surprise and still likely get the kill, and I've found that it performs just as well at mid range, if you use quick short bursts rather than a steady stream. It's a gun you can rely on...plus, it has a cool name!
Then, there's the AK-47. This is the AR of choice until you reach level 44. I use it with Dual Mags, combined with Sleight of Hand Pro for a near-instant reload time, and bursting with it will put that pesky enemy in his place. A very, very solid gun to use...the only thing you need to get used to is the kick. This thing kicks pretty hard, hence why I said burst instead of steady stream. A pair of 3-round-bursts will do the job just as fast as spraying, and waste less ammo.
The Commando is my very best friend. It reminds me very much of the ACR in MW2. The kick is negligible, the damage is nice and high, and again, using it with Dual Mags and SoH gives you a super quick reload speed that has been my savior time and again when faced with multiple enemies. This gun is just plain beast.
However, I realize that these are all high-level guns. For earlier levels, I suggest the Galil. This is a slick operating gun that served me very well indeed. It has good damage, and it's a well-balanced gun overall.
When it comes to LMGs, I have not yet tried the Stoner, except one time I picked one up. I hated that damn thing, couldn't squeeze a single kill out of it, but I think it was more the map. Havana is not your friend for LMGs. The M60 is a good gun, too, if you like LMGs but they are at a severe disadvantage to the other weapons.
As for snipers, the L96A1 with Variable Zoom is a very, very solid sniper. There are only a few maps you can really snipe effectively on, though.
Secondary:
I personally am a huge, huge, huge Ballistic Knife and Crossbow fan, for core. Both are one-hit kills, and the B-knife gives you a huge CQB advantage with its quick stabs and slices.
Perks:
These don't change at all between Core and HC.
Tier 1: Hardliner Pro. Freaking amazing, dramatically increases your odds of getting a bunch of really, really killer killstreaks. With a 5 killstreak, you can drop three boxes and have not one, but four shots at getting those attack dogs or gunship you always hope for. One from switching each box, and one from the original chance in the Care Package. Have fun.
Other than that, Ghost Pro is a must for SnD, of course, and comes in useful. I keep one class with Ghost on it to use when the enemy busts out their choppers.
Tier 2: Sleight of Hand rules this slot for the most part, but the others are all useful, too. Steady Aim Pro is a lot of fun, because you can noscope with snipers decently and you can hipfire your enemies into oblivion. Sights? Who needs those? Warlord is great...two attachments, extra grenades? Freakin' sweet. Combine that with nova gas and scavenger and you can really rule the objective games. Hardened Pro is great in Core, because it reduces your flinch when you get hit. Very, very nice if someone's spamming you with Ak74u fire and you're trying to get off an accurate burst with an AR. Scout Pro is the only crappy perk here...the breath-holding is okay for snipers, but the quicker weapon-switch is almost never the deciding factor in a firefight.
Tier 3: NINJA PRO! Very, very, very useful. Hacker pro is apparently great too (I don't have it) if you're feeling particularly evil. Marathon Pro is your runner perk, combined with lightweight and steady aim to get a really fast, really brutal SMG class that you will usually dominate with. Very good for quick, deadly strikes and getting behind their lines.
I use Semtex for my primary grenade most of the time, but I do love my Tomahawks, as you can tell if you've seen my humiliation videos. If you're good with a tomahawk, it can be telling. He pulls a grenade, but by the time he's primed it, the axe is already in his chest, and you pick it back up and move on.
Tactical grenade...I use the Nova Gas. I love it..it's opaque enough that you can use it for cover if you need to, the deploy speed isn't too shabby, and as an added bonus, it really ruins their day if you toss it into their camping spot.
Claymores are the best equipment for most games. On Domination, though, I stick a Camera Spike a little ways away from the point I'm guarding, and hide. When someone goes to cap it, I pop out, kill them, hide somewhere else. If your camera isn't in an obvious spot, the odds are, nobody will see it. Those things are sneaky.
HardcoreReplace the attachments I mentioned earlier with silencers. Put a silencer on a CZ 75 for your secondary gun. That's it for the guns...
...except that I use a PSG1 with silencer and variable zoom scope for my sniper class, and I have a dirty little class for certain maps.
Havana in particular. Infra-red scope, silencer, M16, hardliner, warlord, ninja, semtex, nova gas, claymore. See a white blob, shoot it. Mostly.
And if that white blob was your team-mate sneaking up behind their lines, tell him it's his fault for not telling the team he was going to be in the line of fire.
With this clan, that should basically never happen. Keep in touch with your team, always, because you will save each other's asses all the time if you do, and you can avoid nasty mistakes like killing the hell out of your sneaky ninja dude.
Don't camp, don't tube, don't be a cheap player...show everyone that you don't need any crutches to be the best!