The one from Zeta called G-Fortress. Core Fighter can connect to the torso part or the leg part and form 2 different crafts or they can all be separate or even together as either a huge, heavily armored fighter or an equally heavily armored MS. Also Victory Gundam, same concept as Zeta Gundam or G-Fortress but much tighter design and more steps in the transformation. But I don't think I have ever seen a toy of that one. The one who transform into that Wave Rider mode isn't stupid either but there are so many variations of that so I don't know what to look for. Many SD Gundams (not excluding or including SD Force) have very cool transformation gimmicks as well allbeight their size and proportion.
The Zeta C Plus (production version). The gray one with the bigass cannon. There was an old 1/144 kit that was great (my first Gundam kit, well before I had any idea what Gundam actually was - found it at a small toy shop and bought it based on looks alone), but the Master Grade version blows it out of the water. Very military/utilitarian looking in robot mode, and the most convincing "plane" in Waverider mode. I find it visually more appealing in both modes than even the much-touted Zeta Gundam or the C Plus Protoype kit, which lacked the hugenormous gun and was molded in orange and white versus the slicker deep gray.
I was always partial to the Psyco Gundam (Yes, it's supposed to be spelled that way) Sure, it turns into a flying brick, but it's got posable fingers, and it's freaking huge for a 1/144 scale model. Mobile Suit mode. Mobile Armor mode.
The MG Zeta ver. 2.0 is certainly a juicy little number: http://211.233.38.221/dalong/mg/m87/m87_p.htm I just bought mine on Monday, but haven't had a chance to put it together yet. But essentially, you've got the classic Zeta design, with articulation and detail up the wazoo (they actually managed to get freakin' waist articulation on the thing, despite the torso transformation), and enough locking mechanisms to prevent it from being floppy. Additionally, Bandai's been trying some new things with their joint tech, and the new polycaps for the Zeta are a much harder, more resiliant feeling material, that are probably less susceptible to wear. To say nothing of course, for all the other bells and whistles that the kit comes with, namely the adjustable display stand, the Hyper Mega-Launcher and Beam Rifle, and opening grenade hatches in its wrists. Plus the compatability between the Rifle barrel and the beam saber blades, a feature that I'm surprised wasn't employed a long time ago. Beyond that, I'm also a fan of the 1/100 Aegis Gundam: http://211.233.38.221/dalong/seed/s2/s2_p.htm Although, if you're just planning to snap it together, isn't the best of choices, because the tolerances in its hip joints aren't the greatest, so it's kinda prone to slipping. But the transformation is freaky cool, changing from its humanoid form to a Mobile Armor with a bizarrely symmetrical form. Seriously, the radial symmetry of the MA mode is stunning, when considering what it turns into. I also love the MG Ex-S (http://211.233.38.221/dalong/mg/m60/m60_p.htm), but if you want the kit specifically for its transformation, it's probably not a good idea. It's an expensive kit, and the transformation's so fiddly, with tiny breakage-prone parts, that it's not something you're going to want to swap back and forth on the fly. I've also heard that the HGUC Asshimar (http://211.233.38.221/dalong/hg/h54/h54_p.htm) is a really good kit, but I can't speak for it myself, since I can't seem to find the danged thing. I kinda want it to see if I can kitbash it into Cosmos, but I've never seen the kit in person, for whatever the reason, to be able to buy it.
The Perfect Grade Zeta lets you stick the saber blades in the rifle. I think you can do it with the first MG too, but I've never tried.
Unfortunately, it's not a feature that they've been very consistant at supporting. But I get the feeling we'll probably be seeing more of that, or similar, in the near future, with Bandai's new trend of including "Special Effect" parts, to allow for more dramatic display options, like the turbine swirls and torpedo trails on the MG Acguy, the Dragoon launching trails on the HG Strike Freedom, Legend, and Akatsuki, and the "Wings of Light" on the HG Destiny.
Ah, Dalong.net... Forgot about that. Now I can prove my point with glorious visual aids. http://211.233.38.221/dalong/mg/m46/m46_p.htm Easily the best alternate mode for a Gundam. All the other alternate modes look like a Gundam attempting to lick its own groin, but this one at least vaguely resembles a plane.
the C1 isnt that different from the other zeta models though. well, it has a massive cannon on the front instead a nosecone. it does hold together a lot better than the first Zeta MG kit (which can barely stand when posed), but the new Zeta 2.0 looks like it's put together a lot better than even the C1.
