I personally use x52 (non pro) and have had an outstanding experience with it, coupled with a home made track clip using facetracknoir.
I'm using the point track protocol and am now unable to play ED without head tracking.
THE big down side to using the free software for tracking is it can be an utter PITA to get working in a manner that feels right for you!
My tracking setup cost me less than £30 including a webcam.
As you can see it's a whole load cheaper than a bonafide TrackIR, now if a naturalpoint trackIR is £100 + better than my setup i'd eat hay with a donkey.
You also have the choice of freetrack, opentrack and facetracknoir, all free so one should fit your needs
I wouldn't go near ED tracker with a barge pole solely due to the fact it does not and cannot provide 6DoF (not much of an issue in ED, but i also use mine for other flight sims where 6DoF makes a huge difference.
Here's some food for thought as well.
http://www.delanengineering.com/
http://www.trackhat.org/
Onto the sticks.
I've said it in other topics on this forum, ALL of the sticks have pro's and con's.
X52 is the cheapest of the "higher end" setups
X52 pro is £50-£60 more, imho not worth the price hike over it's little brother. (more led's and a couple of extra mappable buttons)
X55 similar in price to the X52 pro, more buttons on the throttle base (i think the throttle looks amazing) now it's stick is where the 55 falls flat on it's face imho, no adjustabilty on the palm rest (a big issue if you have small hands) it will get uncomfortable.
The shaft of the stick (giggles) can also flex if you squeeze it, makes the stick of the 55 a no go zone for me.
Then you have the warthog, it's expencive (very evpencive) is apparently very comfortable, has no yaw on twist in the stick so you either need to spend more money on pedals or use keys/buttons for yaw.
For me if i could get an X53.5 which had the throttle of the X55 and the stick of either of the X52's i'd be all over it like a rash!