wait for the special "extended" version. it'll probably be around $25 bucks (and in most places, that would include shipping). i hated the fact that i bought lotr:fotr and then they came out with the extended version. then the second one came out and they did the same thing. fool me once, your bad. fool me twice, mine
Personally I'm waiting on the super duper boxed collector's extended edition with cheese. You know they're going to release all three movies as one set eventually. And it'll probably have a total run time of 20 hours.
DeepDiscountDVD has pretty good about beating Best Buy's release week pricing lately, so I'd look there during release week. It is $17.85 (10 cents less than buy.com, coincidence? I don't think so) shipped now, but I expect they will lower it for that week. Generally, the formula is BB's advertised price - 10 cents, but no tax, so you save more than just 10 cents. But it does mean you wouldn't have it on the release date.
Personally I'm waiting on the super duper boxed collector's extended edition with cheese. You know they're going to release all three movies as one set eventually. And it'll probably have a total run time of 20 hours.