-Pulse lasers are nice, but can overheat your Mech if you are not careful. Balance single shot weapons and pulse lasers.
-The PPCs, Flamers, and LBXAC20s are recommended. Although a great variety of weapons is necessary for any Mech, these three weapons are particularly versatile. The PPC fries electronics and does amazing damage. It is a great assault weapon and a critical one for many missions. The Flamer does a great amount of short range damage, but also creates a lot of waste heat in the target Mech, forcing some opponents to shut down. And the AC20 is the king of damage for in close fighting. If your Mech can mount one or two of these weapons, do so.