I can't do any programming at all, so I've worked with existing engines. I've done my own RPGs in those for all my life, it seems. Programming them myself on the C64, back when I could do simple text based stuff, later making them on Unlimited Adventures engine, RPGMaker 2000, Neverwinter Nights (but prefer RPGMaker - it makes finished games with no need for an original - and is Japanese console style). But I always get stuck on something, typically some code I can't figure out to do what I want, and lose interest shortly thereafter. I finished some on the C64, but man, those are LONG lost...
What I did, then, was write instead, so I could get my moments of glory.

Got them, been there, done that, still haven't given up completely on making that RPG some day. I have one in the works, but it's vanilla RPGMaker 2000, and if I was actually doing it with somebody else, who, unlike me, knew what they were doing, it could go beyond vanilla graphics/music/etc. Only then I would have to actually commit myself to finishing it.

That's scary, you know. Plus, you feel kinda out of your league when working with people who can actually do stuff, and aren't just hacking their way through the engine, forcing it to conform to what you want. Also, you need to know you can rely on your accomplices, so you don't sit around with something half finished and can't get the remainder of the work done in the same style it started out. I have had bad experiences working with other people online in other projects - they just haven't come through when I needed it - and that makes projects die. Ok, usually I finish them myself, but in a case where I can't do everything myself, it would be impossible.
Since I'm a writer first and foremost, I have a plot pretty much laid out, but I'm bad at restricting myself to just doing the relevant plot parts first and add all the fluffing later. Instead, I go out on some sidebranch, lose myself there for a couple of months, then can't find my way back to what I was originally doing and put it away again. I usually come back to it later, but obviously time has passed, and interest waned, especially if I'm dissatisfied with that damn sidebranch that started the whole mess in the first place.
It took me about two years, working on and off, to finish writing my last published (online) "short" story, and before that about three years writing a nation supplement for a pen and paper RPG (those were linked, by the way; it was a short story set in that RPG nation). I'm not sure I can put another couple of years into that damn freeware RPG I've been meaning to make.
After buying all my consoles, I need some time catching up on years of games I missed for, uhm, inspiration. Yeah, that's the ticket.
Still, it would be -sweet- to have a graphic designer for that day I actually do commit myself, fantastic with a composer, and amazing with somebody who could figure out the finer points of RPGMaker coding (yeah, right).

Was looking at RPGMaker XP the other day, wondering if I could figure that out better, but getting a bit daunted by starting over on learning the scripting for another engine.