Out of all the marathons I've done Edinburgh is the worst of them. I agree with the feeling the organisers just want the cash. Average course with awful organisation. The races I'd recommend to anyone are Paris, Berlin, Amsterdam and Disney. All very different races, but all great well organised events.
Paris has the big city event feel to it, an interesting course and based on my experience was very well organised (needs more toilets at the start right enough). It also has a fabulous thread full of great people on this very forum to help you through the training.
Berlin is a great city. One of the big five marathons if that is something you want to check off. Is the course the world record was set on (they year I ran it, not be me though!!), and the finish heading through the Brandenburg Gate is very special.
Amsterdam I probably a bit biased about as I do love the city. The flattest course known to man. If you look up flat in the dictionary it refers you to the Amsterdam marathon profile. If you hate hills you'll love Amsterdam. Starting and finishing in the old Olympic stadium and a nice run out and back along the Amstel river. Smaller in size and feel to the big city races, but very much an international runners race.
Disney marathon in Florida. This was my first in 2007. For a start you can get a holiday out it.
The organisation on this race is second to none. They own the land the race is run on and it shows that they have the free reign to host this the way they want in terms of supporting the runners. It's a marathon with plenty to take your mind off the miles in front of you. Run through all four parks, high five a Pixar character on your way around, great support.
The truth is what ever race you pick it'll be special to you, no matter if it's a huge event or a small local event. The first time you step over that finish line and collect your medal knowing you completed a marathon is a truly amazing experience. If you're anything like me it'll take weeks to wipe that smile of your face.