Like many Tolkien fans who are also roleplayers its always an extra pleasure to be involved with, let alone run, a Middle Earth Campaign. Whilst I do love hack and slay in most of its forms and really appreciate the accessibility of something like DnD the sheer scope, detail and depth of Tolkien's world give not just an enormously rich background of content but also in many cases a reminiscence to part of an adolescence buried in his books. I very much suspect I would have got into much more trouble as a kid if it wasn't for keeping my idle hands busy turning the pages of the Middle Earth. But the formality and detailing of the myth can potentially create a rather dry experience for the players, and it is the experience of the players that count. Above all a game must, by definition, be fun. In this respect I will always bend the rules and this is never more evident than in magic. I do note that Vincent brought one of the most recent sourcebooks which seemed to me to deliberately lack a lot of the fantasy side of things whereas I am happy enough wallowing in 2nd ed.
At about about 5th level the spell lists do actually start to get quite powerful with Mages picking up fire and ice bolts as well as levitation. Flying and teleportation are not much later in the lists and the mentalist spells of the Bards as well as the healing of the Animists can out balance against a non magic using Warrior. As such I tend to give a fighter a couple of extra levels in compensation and a magic weapon.
Of course hubris and power can be balanced against a party's enemies easily enough but also against the culture of the world - basically throwing spells around in towns is likely to get you burned at the steak so it good to have an inherent respect for invocation. Magic is also generally portrayed as being ultimately destructive for Middle Earth in that most magical creatures that inhabit the land are, generally speaking, not supposed to be there. This is typified by the wisdom of Gandalf; given his enormous power, it was tempered by his physical form of an elderly man and where his influence is seen it is often subtle and very gentle - with the exception of the Balrog of course where I just think he lost his temper and needed to blow off steam after a few thousand years.
Anyhows the initial gateway drug for the game are the films of course so I hope its accessible enough for anyone who has seen them but for anyone else wanting to scratch the surface, you can get an glimpse of the incredible depth of the world through an amateurish but surprisingly intricate set of six videos in 'The History of Arda'