The problem with reading a Great Classic these days is trying to say something interesting about it afterwards. I've read it before, but at least I never had to do it at school (who can ever re-read a book they've been forced to study as a teenager?)
So I suppose it's best to just press on as normal, tell you what it's about and what I did and didn't like. The narrator's called Nick, who's trying to make his way in the New York business world in the 20s. He rents a place somewhere on Long Island (I think - it's called West or East Egg) next to a millionaire called Jay Gatsby. You don't meet him at first, but you do meet Nick's cousin Daisy, who's married to a rich buffoon called Tom. He's especially unpleasant, dressing up his instinctive racism with pseudoscience, but Daisy's not a hell of a lot more likeable. I much preferred another woman Nick meets at Tom and Daisy's - Jordan Baker, a cheating golf pro flapper who sounds like a lot of fun.
The book really kicks in when you meet Gatsby himself. He's pretty unassuming, but holds huge parties every night at his mansion for the elite of New York. Everybody assumes he's some sort of gangster, but the most dangerous weapon you see him use is his smile. He's a sort of charming, melancholy ghost. I don't suppose it's much of a SPOILER to say his only goal is to win back his ex-girlfriend Daisy, who lives across the bay. It's a great image - a lonely man at the centre of a whirl of endless parties, who's simply trying to get a girl to notice him. Less romantic saps than me may consider him a complete idiot.
The other character I really liked was Nick himself. He reminds me of a Brett Easton Ellis narrator in his numb, semi-detached approach to everything, but at least he tries to do the right thing at the end when tragedy inevitably strikes. The plot, though, was the weakest aspect for me. I liked the set-up and I liked the ending, but the way it got there was clunky as hell - totally reliant on accident and co-incidence.
It's also worth mentioning the writing - there's some great imagery and turns of phrase which make you sit back and ponder before moving on. Despite that it's an easy read, and fairly short. Suppose that's why they make kids read it.
I haven't seen any movie version of this, but Robert Redford I could totally buy as Gatsby - he's got an air of sadness and a million dollar smile. De Caprio in the new version though? Well, he's usually pretty good in everything. The new Luhrman movie looks from the trailer like it really goes to town on Gatsby's parties, which I suspect is the right approach.