This past CES I was sitting in the MIT/Magico room chatting with Paul Stubblebine about his tape project. His Nagra deck was playing some awesome direct-from-master-tape music. I think it was Duke Ellington. Anyway, when Duke was finished playing Credence Clearwater began and Alon Wolf said to Paul that he hated the song and wished he'd (Paul) never put it in the mix. So Paul had them switch the source over to their crazy good music server and went to work splicing together some tracks from various tapes that he thought Alon would like better. He stood there for about 30 minutes cutting, taping, switching reels, etc. And I have to share that it was like watching Mozart compose. That guy has a serious talent for working with tape.
Anyway, after listening to music from the Tape Project for three days, I have to say that I've never heard a better source than that. It's my only reel (pardon the pun) extended experience with reel-to-reel tape. But it has me sold.
So what would I do with $50K? I'd invest in a nice tape front end, keep what I have for amplification, vinyl front end, loudspeakers, power cords/conditioning, speaker cables and interconnects, and I'd spend the rest on music and rabbit proofing (my daughter's house rabbit keeps me on my toes).
I agree with Gavin about analog tape offering the best possible sound, and Paul Stubblebine being one of the best at his profession. However, I would choose vinyl as the best all-around format. It's easier to store and set-up from recording to recording, less susceptible to the environment and wear, and has great artwork. Most importantly, vinyl offers the best cost-to-fidelity ratio.
If I only had $50k, I'd spend about $10k on the system (about 20% of that would be towards acoustics) and the rest would be on the vinyl. But that would only give me about 1/10th the vinyl have now. Maybe I couldn't do this!?
That's tough. Considering what good vinyl costs these days, if I had to start over I'd probably buy a Sooloos, a Devialet Premier-D, a pair of Verity Audio Rienzes, a used Porsche Boxster S and borrow all my friends CD's....
Or, Grab an AVID Volvere/SMEV (not sure what cartridge), Used CJ PV-12 and MV-50 (send them to CJ for Teflon cap upgrades) a used pair of MartinLogan Aerius and my 1000 favorite albums.
The tape thing is really fun, but there just isn't any software to make it viable. It's a great concept in theory, but no music to listen to.