Just popping in for a few words.
I have never been a Halo fan, I've always found it a series that is stunningly average, repetitive, and with shoddy level design and even shoddier story - other than the first one, which is honestly damn great, and the first few levels of Halo 2, the series has always left me disappointed and pissed me off because reviewers throw out perfect scores at it so freely and gamers everywhere radically declare it as the greatest game of all time.
And sure, the multiplayer has always been solid, but a so called perfect game, like many claim Halo is, shouldn't need an excuse - the latter half of Halo 2 is particularly dull.
HOWEVER. Having said all that, Halo Reach is awesome and very much surprised me. It's not perfect, no, it still suffers from a lot of typical Halo flaws, but it's by far the most polished up entry and it tells a good story, so I'd have to say, other than Combat Evolved, it's the best of the series.