Since my previous (useless) post, I have found that I actually have two boxed sets of Beethoven on LP:
Szell/Cleveland (1970) - avoid this one, for sure; sonics stink (very inconsistent, especially from side A to side B in the same symphony!), though I agree with some of the interpretatoins (the funeral march in 3 is just great!)
Toscannini/NBC - I have actually 5 sets of this. (don't ask) The recordings are great and the performances are great. The sonics (all mono) suffer from their technology, but are at the top of the pack for the time. If you can find this cheap and in good condition, get it and listen. I would not go terribly out of my way to find it, though, nor would I pay top dollar, but it is absolutely essential to have and hear.