I'm fine with Rice at #1. Aside from being the most dominant receiver I've ever seen... the guy went to the Pro Bowl at 41. If people want to call him "soft" go ahead, but I think it takes an Iron Man to get creamed by 230lb safeties when you're old enough to be a granddad. His conditioning was legendary and he single-handedly redefined most players' offseason training regimens (hill training, nutrition, etc).
Yes, he was fortunate enough to play with Montana and Young (Montana I always though of as being the best QB ever), but he also made a Pro Bowler out of Rich Gannon... yes, the same Rich Gannon that was cut by a half-dozen other NFL teams. So it's a chicken-and-egg scenario.
Not only does Rice own every receiving record out there, but the next guy isn't even close to any of them.
If I had a top-five it'd be:
1. Rice
2. Montana
3. Taylor
4. Brown
5. Larry Allen (yes, I'd put him before Munoz)