Sub-Machine Guns
MP5
This is the most commonly used of all sub-machine guns by far, and probably the most used gun in the game. It's a very reliable gun with good accuracy and power. If you can aim well then the MP5 will be a good gun for you, if you can't use the mp5....well...learn!
Even when things aren't going so well you can usually afford an MP5 and that's what's great about it, you'll always have the mp5 as a way of digging you and your team out of a hole. It has a 30 round clip which is enough to carry you through most fire fights, aim at the head and it shouldnt be too difficult to get a couple of kills per clip (of course, that's if you're good at avoiding death primarily). It's also decent for mid-range battles.
TMP
This is like the sub-machine gun version of the glock 18; it has a good rate of fire but is very weak, the weakest of all SMGs infact. Again the clip size is 30, but that doesn't help much either when you look at the accuracy of this gun. It's very shoddy and the recoil for such a small gun is terrible.
Sometimes due to money restrictions, you can't afford an MP5 and are left with this gun, but I think even then you're best of buying a Desert Eagle and hoping you can pick up a gun along the way, that way you'll be saving some money for the next round too. One good point is that it's silenced so if you're skilled enough you can sneak up behind an opponent, dispose of him and steal his AK47.....this gun is CT only.
P90
A decent SMG, this used to be the most used gun in the game...until the CS team toned it down a bit because it was being over used. It was extremely accurate and powerful making it extremely easy to use. Now, however, it takes alot more skill to use the P90 as it's less powerful and much less accurate than before. Probably best used in close quarters battle this gun has a very nice rate of fire, and a massive 50 bullet clip, meaning you'll still be firing away while an opponent reloads his MP5.
I'm unconvinced about the accuracy of this gun...at times it can seem ok, but most of the time I use it, I don't get very far which is no good if I've just spent over $2300 for it.
Mac 10
This is yet another gun that doesn't get used very often in CS, in comparison with other guns. It's ok in the rate of fire department, and holds up in the power area, but accuracy is where it falls down....badly! The accuracy on this gun makes it worth saving the money for the next round, death is imminent regardless.
It's not that bad really I suppose, I just felt like dramatising hehe. This gun is ok if you are rushing, your opponents dont expect you, and you can get quick headshots in CQB. Other than that, give it a miss and if you do buy it, pick up the first alternative gun you see....unless it's a TMP but even then it's a tough call.
UMP
This gun has a slow rate of fire and only 25 rounds per clip, meaning that some people tend to steer clear of it where possible. It does, however, pack in some nice accuracy and a fair amount of power...in the right hands, this can be a very decent gun.
Probably best in mid-ranges, rather than CQB though, because of it's accuracy and slow rate of firing. If you do end up in an enclosed space then you won't last that long before you need to reload, which also takes quite long so try to avoid that scenario. Not a bad gun at all for the $1700 you'll pay.
Assault Rifles
AK47
Here we have one of the most popular guns around, people either love it or hate it, but the great majority tend to react favourably when you bring up the topic of the AK. It is the least expensive rifle in the game at only $2500 definitely a bargain, especially when you consider that it's the most powerful assault rifle as well as having 30 bullets in the clip.
So why so cheap? well, I didn't mention the recoil yet....on full auto this gun is about as inaccurate as they come. Only upon mastering how to use this gun will you appreciate how good it is. In close quarters battle it is superb, it's powerful, good rate of fire and on full auto you can empty a small space very quickly. For me though range is where the AK47 excels, if you use burst firing. This gun can be used as a sniper rifle but without the scope, that's how good it is from distance. Two or three accurate shots from this gun across a mid to long range distance will hurt an opponent pretty badly, stop, let the crosshair recover, and fire two or three more and he'll be dead....often he'll be dead before you even get to fire the last few bullets. Learn to handle the recoil and you'll love this gun. T Only.
SG552 Commando
Much like the AK47, this gun is good in both CQB and long range scenarios, but it tends to be a lot more accurate when using burst fire obviously. It is less powerful than the AK but comes with a built in scope to assist you in long range fights. When you're zoomed in the rate of fire does drop noticably but accuracy is helped which is what you want from range.
A lot less effort is required to learn how to use this gun than the ak, again because of the recoil issues, overall a good gun....Terrorists should feel safe with this 30 round gun in their hands. It's more expensive than the AK47, but that doesn't necessarily mean it's a better gun, maybe it's just easier to handle. T Only.
Colt M4A1
The favourite gun of the CT masses, the colt is a great gun and is more often than not likely to be compared with the AK rather than the Commando. It's the cheapest of the two CT assault rifles and represents more value for money than it's CT counterpart, the Aug. It has a 30 round clip and is also pretty darn powerful.
The accuracy on the colt can be quite wayward on full spray, so you're best bet again is to stick with burst firing unless in CQB. The main difference between the Colt and the other assault rifles is the silencer it comes with. This can be a great tool when used effectively and before the enemy can work out where you're coming from they can be almost dead. The silencer may make the Colt slightly weaker, but it makes it all the more deadly. CT only.
Steyr Aug
This gun is very popular, like all assault rifles, and is the CT equivalent of the SG552 Commando. It is more expensive than the Colt, which is probably mainly down to it having an additional scope for you to use.
It's a pretty powerful gun with a good rate of fire, which again is slowed when you're zoomed in, although it does take a bit longer to reload than the Colt does, or the T's commando for that matter. Overall though, a great gun and worth the money if you can afford it as it's pretty accurate, and even better in bursts. An Aug on full auto will clear a small room pretty darn quickly. CT only.