Another couple of RF advantages are noise (or lack thereof) and the ability to see through the 'finder as the exposure is made. The key area that these advantages apply to is that of candid street photography.
Also rangefinders tend to be fitted with prime lenses, which have clarity and contrast in spades.
An SLR can wear either primes or zooms. Whilst you don't get to see through the finder as the exposure is made, you do get to see through the lens the rest of the time. This does away with any parallax error and also helps with the positioning of grad filters (which may be of interest if you're doing landscapes).
For what you want, I would personally go the SLR route. Others may feel differently. If you are set on a manual focus Nikon then I would also consider the secondhand market. Ffordes do decent kit, are honest about the condition, offer a warranty and a moneyback guarantee if you're not happy... ...and there isn't much difference (other than cost) between an FM3a and an FM2n.
Other makes are also worth a look. Canon MF bodies are good and fairly bulletproof and their prime MF lenses (speaking as a devout Nikon-worshipper) are just plain lovely. They also have the advantage of being dirt cheap (don't you just love the digital revolution?!)
I also wouldn't discount AF bodies. The Dynax 5 might not have been for you. Try an F80. I love the ergonomics of mine, and it'll let me do my own thing when I want to or operate as a sophisticated film-in-brain-out PAS if the need arises.
One final thought - don't get too hung up on kit. I've taken some of my best shots (okay, not exactly an exacting standard in present company! ) with a forty year-old Pentax S1a and a selection of equally old M42 screw-mount third-party lenses. One APUG subscriber of my acquaintance favours Holga plastic-lensed "toy" cameras, and produces stunning work with them.
The most critical factor in photography is generally found standing about a foot behind the camera. Pretty much all else is secondary. There have been a couple of absolutely excellent articles in Lenswork on the subject, which I'd highly recommend.
I hope the above ramblings have been of some use. They're free and I assure you worth every penny! At the end of the day though, what works for one person may very well not suit another. I hope that whatever you finally choose will prove to suit your way of working.
All the best,