A synopsis of what i've learned so far that i will base my decision on.
240sx: I've liked them for awhile. Everything that I knew about them has been reinforced. They are fun, small, agile, easy to find parts for, easy to work on, easy to find. the cons are superficial. yes, they are a bit fanboish. that's not really a fault of the car, if anything "it is what it is" i.e they are popular for a reason, see above. i'd like to someday do an sr20det swap, it would just be a matter of finding the right source for the right price, and then subsequently having the money to pay MA for their fine knowledge of nissans. Of all the cars listed, the 240 is the most likely because of the cost, and the selection.
Porsche 944: The idea I can't shake. As a company, I love porsche. they make drivers' cars. period. the 944 would be a lot of fun and not quite as dime a dozen as the 240. this of course comes with negatives. parts are fewer and more expensive. maintenance o'plenty. it's also tough to shake the label of being the poor man's porsche. i'll never own a boxster because of this, so it's hard to think of picking up somewhat of a predecessor of it. if the right one comes along at the right time, it would still be hard to say no.
Maza rx-7: The most appealing idea of the rx-7 is the potential for an ls1 swap. that being said realistically i will never do an ls1 swap. the rotary is a cool, niche engine, but nothing that's horribly appealing. the turbos are a lot of fun, but horribly unreliable to the point that it's a well known joke. I can't see picking up an rx-7 when i prefer that 240 and in stock form they are so similar.
Bimmer: the e30 is an acquired taste. one which i just haven't stumbled upon yet. looks aren't everything, but you still want to be seen in your loving project and be happy with it. the e36 is very appealing. the problem with the e36 option would be finding the right one. i'd prefer a coupe and require a 5 speed. the i6 is a great engine that i could settle with.
Supra: Similar pros and cons to the rx-7. fun, quirky, incredibly appealing because of the possibility for a high powered swap. will i ever drop a 2jz in a mid 80's supra? very low percentage. again, with so many 240's out there, i can't see choosing a supra over it.