Don't bother seeing the rest of the live-action films. Waste of money, only the first one was decent unless you just want to see other transformers transform. I do follow many other Mech series, but that's all in the Mecha forums. :D Gundam, Robotech, The Five Star Stories, Full Metal Panic, and many others are good to watch not just for the mechs too. My sig and avi set is taken from Broken Blade, it's a short anime (like 6 episodes) but really enjoyable. I can tell you more, but it's off-topic. ;P
I am a huge transformers freak though. When I saw the first of the new movies a few years ago, after not having seen transformers in like 2 decades, it sent shivers down my spine when Blackout started to transform in the first scene of the movie. Always been a big fan of Mechs though, loved the computer game series of mechwarriors. Never seen any mech animes though, I probably need to look into that. Your sig looks like some kind of mech whats it from?