With respect to text, today I would suggest the one volume
Fiftieth Anniversary edition of 2004 (or its reprint in 2005 which contains more corrections). This was a fresh effort
'... to produce a text as close as possible to what its author intended, as far as that could be conservatively determined.' Tolkien's publishers and the Estate agreed with the 'fresh effort' proposal, and Hammond and Scull got to work (they explain the edition in much more detail in their Reader's Companion)
It's also quite beautiful (has a slipcase) though a bit on the expensive side -- it's similar in look to previous one volume 'Red Book' editions, which I would recommend also for beauty.
Quote:
The Lord of the Rings by J.R.R. Tolkien. 50th anniversary edition. [Ed. with a note by Wayne G. Hammond and Christina Scull.] London: HarperCollins; Boston: Houghton Mifflin, 2004. Beginning with late 2005 printings, the edition contains further emendations and a new, enlarged index by Hammond and Scull.
I only have one
very small 'problem' with one of the notes from H&S, but it does not affect the tale proper in any case.