Choices, choices!
Nikon cameras are scarcer on the market and some bring premium prices - but if you are shooting Nikon SLR's, you are used to the focussing direction and that is a factor to consider.
Models like the Nikon S2 (50mm finder only, but one of the best finders of all time) can be had for decent prices -$500 and up and they usually come with a 50mm lens. The 50f1.4 is the one to get here.
The S3 is more expensive, but it does have 35/50/105 frames in the finder (the 35 is a bit of a "search" to find and all the framelines are on at all time). A good user S3 should run $ 900-1000 + the lenses. The 35f2.5 and the 50f1.4 are reasonably priced and the 105f2.5 (big and hevy but Oh so good) would set you back another $ 1000 with some careful shopping. That would be a nice kit and apart from not having a wide angle (Nikon's original 21/25's are pricey) you can always try to chase down a Voigtlander 21/4 SC mount. It is out of production, but they do pop up used at decent prices.
In the Leica line up, the M2 is my favourite, simple and reliable and with the 35/50/90 frames it covers most of what you want. They tend to range from $500 and up too, but the lenses are more expensive as they are M8 compatible and get snapped up quickly. However, there are alternatives, the Voigtlander lenses are very good, sometimes surpassing the Leica offerings as do the Zeiss ZM line.
The M3 is nice, but does limit you to 50/90/135 and in my mind, the 35 focal length is the main reason for a rangefinder!
Later versions. the M4-2/M4-P and M6's are fine to, with the added advantage of the M6 that is has a meter built in. Again, prices go from $700-1200 depending on model/condition.
With the Leica you pay premium for the lenses, sometimes this is warranted (35/2 Summicron's, 50mm Summilux Asph's), but in many cases you pay for the name rather than performance! It would probably cost you another $1000 over the S3 kit to get the 35/50/90 (if they were all Summicrons) and a M2.
Of course there are the Zeiss Ikon ZM camera and various Bessa cameras. However, they are all "modern" and to some extent that "vintage feel" is missing.
The Leica screwmount cameras are fun and truly vintage. However they are all 50+ years old. They are all limited to 50mm finders (except the IIIg with has a 90 mm too). Lens choices are plentiful, but apart from the Voigtlander LTM lenses, they are old and usually suffer from coating damage,haze or scratches. They are also a pain to load! This said, a IIIf in good shape with a 50 collapsible Red Dial Elmar 50f3.5 is most likely the apex of "mechanical" cameras. Dials spin around, things whirr and click and you will probably spend more times playing with it than taking pictures.
The black IIIf on my site is a replica. An original black IIIf would cost upwards of $ 50 000 as they were only made for the Swedish Army and only 125 were made. It had three Crowns engraved on the back. I am thinking of doing 4 crowns on mine and call it "inflation".
One advantage that the Leica's have over the Nikon's (and Canon's rangefinders which can take Leica screwmount lenses) is that there is plenty of service available. The Nikon's can be a bit difficult to fix and service, though I find that they require less of it than my Leicas.
In your situation, I would probably spring for a Nikon S3 and a 50f1.4 and get used to the camera, later add the 35/2,5 and the 105/2.5. If you feel that you need something wider, always keep your eyes peeled at the classifieds here on RFf for a 21 or 25mm VC lens in SC mount.
Hope this helps,
Tom