^^ Have to admit, I don't think that I've ever used an unsilenced pistol.
I think as a beginner class, it's either MP5 or the M16. The sniper rifle isn't worth bothering with at that point and the LMG isn't the best bet for a new person as the recoil probably, for them, won't be the easiest thing in the world to handle.
Regarding the sniper spots, that's actually a very good point. This time around I've been trying to get all the sniper achievements and I've come to know a lot of nice sniping spots across the maps, which will undoubtedly stand me in good stead going forward. Most maps have decent sniping point;
Ambush - Take your pick. Any of the elevated buidlings (if you have claymores). On the main road across B looking directly down one of the three paths that they can use to come up to B. Right at the back of the map on A side looking up the path towards B.
Backlot - The building with two sets of stairs, one at either side. The building at the opposite end of the map with the machine gun nest. Although, with both, don't be obvious and just sit in the most visible part. Tuck yourself away somewhere in those buildings and shoot at angles.
Bloc - Pretty much sniper heaven, but even now, trying to get the sniping achievements I still avoid that map like the plague.
Bog - At the top of the map, behind the container at the top on the left. A surprising one is just off the top of the mound at B. You'd be surprised how many kills you can pick up lying prone just off the top and the side of the mound. At the bottom of the map, if you're ultra cynical you can camp at your spawn point at the back of the building and shoot people coming through the shop. There's a great sniping spot on Bog in Old School, if you start at the bottom of the map, just go left out of the gate and in front of you there's a fruit stall, you can jump up on top of the stall and then jump up again and get on top of the blind. From there get into prone and you can see all across the map without being able to be seen yourself except from directly ahead.
Countdown - Anywhere around the periphery of the map, on top of the tankers/tanks, or inside the hangers.
Crash - The tall building is probably too obvious. Likewise the blue building, and the building directly opposite near to C. Probably the most cynical spot is if you start at C break left and go to the edge of the map. At the end there you can see all the way up that path that comes down from A. Get into prone and just pick them off on the way down. Most likely, because you're in prone and in the grass, they'll never even see you.
Creek - Too many. On top of the roof of the building next to A is a favourite, but again, obvious. Given the nature of the map though, there are so many spots for sniping, it's hardly worth trying to mention them all.
Crossfire - Again, the building at the top of the map, and the two at the bottom are obvious. The two best spots so far, down at the bottom of the map looking up the road, go into prone next to one of the cars in the middle of the road. Other than that, if you're being pushed back onto C, just go into the building behind C and hide either inside the doorway at the top, or behind the cooker in prone.
District - Only really found two decent spots on this one, and they're at either end of the road where B is. From either end, with sniper scope, you can pretty much see all along the road.
Downpour - One spot, that's all I've found really. At the bottom of the map, the greenhouse where A is, just to the side there's a garbage skip. Get in it and go into crouch. From there you have a clear view of the door of the building at the top on the lefthand side.
Killhouse - Who knows, only played it once. Given the size of the map though, sniping is unlikely.
Overgrown - Loads, but the best two for me; If you start on C side, the bridge on the left side, get up on the roof of the small building overlooking the bridge. The other one, if you start by the petrol station, right at the start go behind the oil drum and you can pick them off as they try and get control of B. A good spot is actually the wall by the bridge. From there you can pick off anyone coming towards/over the bridge from C, and also double back to cover B if you're in danger of losing it. There are a few more though; If you go into the building by B go right to the top and get onto the ledge of the hole in the wall that looks out onto the bridge coming from C. Not only do you overlook that area but if you get onto the ledge and crouch you can edge out and look out over the ravine and see the door of the building that's by C. You can take out anyone running through there, or anyone who's on the roof of that building.
Pipeline - The top of the map is obvious but I must admit, I don't snipe on this one.
Shipment - Not worth it.
Showdown - Again, I don't snipe this map.
Strike - Either, the top of the building by C, if you have claymores, or, the top of the steps of the building up from A. From there you can just sit at an angle and pick off anyone approaching A.
Vacant - Only found one spot on this. Outside the hanger, near A, there's an oil tanker. If you're by this you can see all the way across the map. Generally, there seems to be a lot of people running along here for one reason another. Easy kills.
Wetwork - On either bridge, or, if you're feeling lucky, any of the half decks in the middle of the maps.
Broadcast - In the building next to A. You can see anyone in the main reception, or anyone running towards C.
Chinatown - I don't bother sniping.
The best advice for sniping, if you can, protect yourself, ie. claymores. Always use a stealth configuration, ie. UAV Jam, dead silence, Iron Lungs. Finally, try and shoot at angles from behind cover, rather than taking the easier, but completely exposed shots.