Alexx:
Tolkien reading order, IMHO:
1. The Hobbit (which you can pick anytime and finish in a few hours)
2. LOTR, starting with FotR, then TT, then RotK (do NOT start with RotK!!), and make sure you read the Appendices in RotK.
3. The Silmarillion
4. Unfinished Tales
5. The Children of Hurin
6. The History of Middle Earth
7. Anything else you can get your hands on.
Actually, I would say only the first three matter in terms of order. The rest is as you like it. The Silmarillion is a much more complex work than is LOTR, and of course, The Hobbit is the lightest of the bunch. Unfinished Tales is something like a second volume of The Silmarillion, though that is not an accurate statement by any stretch. A lot of 2nd Age and early 3rd Age stuff is in Unfinished Tales (ASIDE: Alexx, fyi, The Hobbit and LOTR are set at the end of the 3rd Age. The first fall of Sauron occurred at the end of the 2nd Age. The 1st Age was covered in The Silmarillion).
Read The Silmarillion before The Children of Hurin, as the latter is a tale expanded from inside of The Silmarillion. The Children of Hurin is also very tragic (I have always thought it had a very "Wagnerian" feel to it), so don't expect a happy ending!
The History of Middle Earth (12 volumes, since out in a few omnibuses (omnibi?)) is a scholarly work by Christopher Tolkien, based on JRRT's notes from 1918 to 1974. It is not a fiction, per se (though it contains very early versions of many of the Silmarillion stories), but it is rather a history of how JRRT created Middle Earth. Not light reading, and if you are not a complete and utter Tolkien fan, or a scholar of 20th century fantastic literature, you probably will not like it.
There are a number of other, non-Middle Earth related stories (Farmer Giles of Ham, Tree and Leaf by Niggle, The Smith of Wooton Major). There is also The Road Goes Ever On, with Donald Swann (I believe) which is the songs and verse from Middle Earth. I don't have this last one, and -- someone please correct me if I am wrong -- I believe the verse is set to music.
Just my thoughts on how to read Tolkien. There are no doubt other, yet equally valid, points of view.