To start with, I am not an expert, so this is just for fun.
The Timberwolf is a 75 ton Clan mech, most popular with Clan Wolf (mech affiliations). It is fast for a heavy mech, and is a match for many inner sphere assaults, though you must never forget that extra armor is always a big advantage. It's offical primary configuration consists of a nice mix of LRMs and ER Lasers, while also having a medium pulse and some machine guns thrown in. I feel that those MGs are a bit of a pointless liability because of the ammo lying around, unless you are fighting infantry. Also, there is a bit of a heat issue, though you can work out your firing patterns to compensate.
Other Wolf mechs that I've found useful are the Linebacker (in the A congifuguration it's a fast, long-range sniper) and the Pouncer (with it's targeting computer and mobility, it's definitely an upgrade on the Adder--but I wish it had more heat sinks). The Gargoyle, Clan Wolf's favorite assault mech, on the other hand, is completely useless, in my opinion. The speed factore does not make up for the low armor and armament levels, and there is no reason to field it instead of a Timberwolf. That leaves the Wolves without a common front line assault mech, unfortunately (more on that later).
The Marauder has heat and armor issues as well, but it's a frightening heavy mech.. The Archer is well-armored, and if using the LRMs alone, is okay for heat, but the Riflman is almost crippled by heat. Especially when you consider the all-energy variant! There are some less-popular mechs that are a little more effective in certain areas, like the Grasshopper, which has a great close-range punch. The Crusader is also a very well-rounded machine. But, I still like the other four just because they are such classics! To bad their original forms will be forever hidden for most of us.
A few of us had found that the original clan mechs seemed under-developed, since you can easily upgrade some of them to much more effective fighting machines. Then I found that FASA's original designs had in fact been much tougher--apparently too tough. Check out My Page on the subject. Being a clanner, I'd like to see those mechs in action, and get my hands on some megamek files for them. Unfortunately, I don't have HMP...but The Drawing Board now works with megamek! And I can tell you, they really do kick ass.