Most PRACTICAL, yet good sounding REEL to REEL ???

How do you intend to use the open reel tape machine? If changing speeds and splice-editing aren't important, you could start with a REAL CHEAP experiment: any old VHS Hi-Fi machine (which is any of 'em built in the last 7-10 years or so).

You can pick up a used one for $5-25. They all have a flat frequency response of 20-20KHz and a S/N around 90-96 dB, which holds for all 3 speeds. That's better than you'll get with any open reel home recorder and many studio ones as well. In my experience, the only limiting factor on using the slower speeds is tape dropout. Use a good enough tape and you can put 6 hours of stereo on a single cassette.

Caveats:
1) There may be some considerations about machine-to-machine compatibility, but the tracking adjustment (whether manual or auto) should take care of that.
2) Most of the later and cheaper VHS Hi-Fi machines have automatic level control; I used to have a 1st gen. Sony VHS that actually had recording level controls for each channel, plus a headphone jack. Still, with a dynamic range of 90-96 dB to play with, the auto-level control shouldn't be *too* obtrusive.

At least, at $5-20 it wouldn't cost much to experiment.

You can still get VHS blanks at the local grocery store. Where ya gonna get open reel tape?

04-28-07: Alaric
Tandberg. If you'd rather collect/make cassettes , Nakamichi.

At the store I worked at, we also carried Nakamichi. I did an A/B record/playback comparison of the Nakamichi 1000 ($1600 in late 1975) vs. the 3-head Tandberg 330 ($550, I think) cassette deck. In that experiment, the Tandberg sounded much more like an open reel deck. The Nak still sounded like a cassette--sort of thin and threadbare through the upper bass and midrange. I played the comparison for my co-workers for a sanity check, and they agreed. And yes, I did azimuth alignment on both decks before recording.

Johnnyb53 , try the Nak ZX9. It was essentially a Dragon with manual head adjustments for bias and azimuth. Astounding cassette deck. I fed mine CR tape and used a Tandberg amp/pre and a Yamaha PX-2. Got very nice results , IMO. :)

I have several Naks including the 480, 550, and 680ZX, which was the baby Dragon. I have also owned the 700 and 500. All in all Nak made some excellent decks in the day, right up to the very end. However, one of my favorites is the Tandberg A440 which easily held its own against the 680ZX. It may not have had the fancy features, but it certainly made excellent recordings and sounded great during playback.

i own 5 reel to reel tape recorders. why? i like to record vinyl and do alot of editing (choosing only the tracks i like). secondly, you can plug in microphones, even really cheap ones, and have an absolute blast recording music or even voices. my 1st machine was a concord, and the whole family gathered around and took turns reciting poetry or singing songs into the little microphone. we acted like idiots and had more fun than you can imagine. later i alligator-clipped wires to our blaupunkt am/fm/sw radio speaker and recorded classical and broadway shows.
these days you're better off with a hard-drive (alesis) recorder unless you can really play an instrument pretty well and have some decent mikes. if only more places would fix reel-recorders (and do it right) it would make me VERY happy indeed! as for old pre-recorded tapes, i just wouldn't want to take a chance with them shedding and possibly ruining a nice clean tape deck. but if you really want a tape deck in 2007, TEAC/TASCAM sells many of the (mechanical) parts you would need to get them to run like new again if they needed work. AND i strongly prefer decks WITHOUT AUTO REVERSE. pro-decks run in one direction and the reason is all too obvious. reliability, tape alignment, fewer heads/better quality.
of course, if by some miracle you find a nagra or stellavox in perfect shape that a neighbor will let you have for $500, you might want to make a quick run to the bank...!