[Suzerain of Sheol]

Actually, if you want a good introduction to Tolkien, look for The Hobbit, instead. It's only 300 pages and the plot moves a lot quicker (though it's a bit more... childish, I guess. It's still an awesome book). It's a really easy read, so it won't slow you down much if you want to get on to Lord of the Rings, and it sets you up in the world a bit, which can be helpful. I mean, it is, officially, the first part of the story, but it isn't absolutely essential that you read it first to know what's going on. It's just recommended. ;)

Lord of the Rings ups the ante on everything and gets a bit more bogged down in the world-building details, but it's still a great story and it's not *that* bad to take in for the first time.

The Silmarillion, on the other hand... uh, yeah, unless you really, really love Lord of the Rings after you read (particularly the world it takes place in), I'd stay away from this one and any of his other "extended universe" books that were published after he died. These are the ones that have 1,000+ characters in them (half of them with names beginning with the letter F) and spend entire chapters doing nothing but describing the landscape.

Hopefully, that's of some use as a guideline, at least.