Mechwarrior 4: Mercenaries

• Get MekTek. Then get NetMech IV. Actually, I think you can get NM IV and it'll download Mektek with it. Either or, hundreds of mechs added, tons of weapons, maps maps maps, and people still play online religiously.

• People like to jump-jet PPC. Plan accordingly. I recommend "missile-boating", i.e. stacking your mech with a lot of missiles and bombarding from afar as soon as one of those beam-spamming nutjobs pop their little cockpits over the visible horizon.