Original wireframe (or the C64 port) for me.
Oh yes, I spent enough time on FE2 & FFE too, but C64 version feels most enjoyable still. I have Oolite too, but I've fallen to the dark side and haven't
played the game apart from testing OXPs (mostly those I'm trying to make). Must be over a year now since my last session other than OXP testing.
Hmm, maybe a bit background to clarify where I stand might be in place:
<boring rant>
I got my 1st own computer for Christmas 1985 (was 10 then), Commodore 64. Then I read a review of ELITE and was blown away. Hunted for the game for a while, until got a copy from a friend - copied a C-cassette full of games as was usual at that time, one of them was ELITE.
My grasp of English was much less than basic then and of course the pirate copy had no manual with it, luckily the crackers had included a list of commands at game start. I meticulously took notes of the list on paper, and it did help albeit I didn't understand half of the stuff even with a dictionary (my mom's English for travellers pocket-dictionary from 1960's

) at hand.
Anyway, I fumbled around and eventually managed to dock at Leesti a couple of times - the dead slow approach, hoping the shields will last long enough... I didn't understand the concept of "save game" then, so my interest vaned rapidly.
A couple of years later I read and article about ELITE in a games yearbook that revealed stuff like the Constrictor mission etc., that article rekindled my interest in the game. I even managed to scrape enough pocket money together to buy a legitimate copy of the game. Now I was better equipped too, I had a floppy drive so saving the game was painless. Made it to Dangerous with one commander (always smuggling contraband and thus being offender with police escort most of the time), and to Deadly with another (buying only legal stuff, and seemingly progressing faster), until other interests took over.
Then come Frontier, bought a boxed copy as soon as it came available. The problem was I still had only the good old C64. To my luck my elder sister lived only 5 km away, so I could play on her 386 quite often, of course not as often I'd really liked, but anyway

. Configuring config.sys & autoexec.bat to get the game running was an adventure in itself

. Later I even installed FE2 on my mom's work computer, same hassle wit DOS there. I still have that 486 stored in basement as she got to take the PC with her when she retired. Well, at that time there was much going, like Master of Orion (me geek?

, hell no - umm, ok maybe a bit on the nerdy side...

) and high school with all associated allures, so FE2 didn't enchant me like ELITE had done. And at home I still had only C64, playing Space Rogue and ELITE every now and then to satisfy my space flight desires.
I bought FFE too as soon as it became available, and boy what a ride it was on my shiny new Pentium. And because I had moved away to attend university, I had too much freedom => almost flunked a couple of courses because I just had to do all hand-coded missions with the same commander

. Spent so much time learning the ins and outs of the game and later hacking it that the C64 version wins my vote here by quite narrow a margin.
Maybe the deciding factor are the 'nostalgia trips' I've made beacuse of ED Kickstarter: DosBOX & FE2, WinJFFE, glFFE and CCS64 & ELITE, of which the most enjoyable has been the last one. I immediately found my space legs again, and this time I will make it to ELITE. I really didn't enjoy the emulator until I got a digital joystick for it (Speedlink Competitipn Pro, a Competition Pro 5000 replica for PC, USB connection) as a Christmas present from a good friend of mine. Incidentally I had (and still have) a pair of Competition Pro 5000s for my C64.
</boring rant>
So, playing C64 ELITE on emulator since Saturday, my new commander is Competent and has died only 3 times: twice blasted by pirates' missiles before I could afford ECM and had only the forward Pulse Laser, once becuse the Docking Computer decided to do the dead slow entry and a Shuttle or Transporter launched to my face and DC had almost depleted my front shields.
<mumbling>MUST become ELITE on C64 & Oolite before ED beta phase</mumbling>