Bramish
aka Maggoty Grasshoppe is a 33.67 year old boy, has been a member since September 7, 2005, has scored 34,495 submissions, giving an average score of 1.97, helping 512 designs get printed.
A couple are The Time Machine by H.G. Wells (I'm sure you thought of that one),and How to Survive a Science Fictional Universe by Charles Yu. I'll try to think of some more.
Also, I have to recommend Jorge Luis Borge's Ficciones, if you haven't read it yet. It doesn't necessarily involve time travel but there's a bit of time... bending. Anyways, it's my favorite book/collection. Aside from The Third Policeman.
Slaughterhouse Five is my favorite book, not to mention my favorite time travel yarn.
I read one in an American Literature course I took in college: it's called Kindred, but it's more 'historical fiction' than anything. It's about a black woman who mistakenly goes back in time to the slavery controlled south, but then has to save one of her ancestors, as a boy (who's also the son of a plantation owner), to ensure that she is actually born. It's pretty interesting, and well written enough, and there's enough plot twist to keep you reading, but it's all up to whether or not that type of subject matter would appeal to you.
I just read 11/22/63 even though I'm not a huge Stephen King fan. I was interested to see how he would handle the time travel aspect and the central premise of undoing JFK's assassination was kind of intriguing. All in all it was a decent yarn with some interesting stuff about the butterfly effect. He also managed to deal with some of the paradoxes that inevitably come about from time travel.
The Dechronization of Sam Magruder, by G.G. Simpson. This short novel isn't the best sci-fi story, but it's notable because Simpson was one of the world's greatest paleontologists, and a major shaper of modern evolutionary theory. He uses his character's time travel in part to describe his own personal views of dinosaur behavior and biology, some of which have been challenged or overturned by new evidence- (e.g. he is adamant that dinosaurs were dim-witted and cold-blooded), so it's neat to see a bit of the scientific debate seeping into popular fiction.
Not a novel but a short story: Poul Anderson's "Flight to Forever" from the 1950's. A very cool story about a time traveler who can only travel forward in time, into the very distant future. You might find it in Sci-fi anthologies or collected works.