The last two are more personal taste, Small God's is Terry Pratchett's best book and Ender's Game is unarguably the best Sci Fi of all time.

But yeah, I'm not surprised you've read/agree on most of them, most of them would be in any top 10 list of a heavy reader.

If I had to pick one as the most important to me though.. Hitchhiker's is a book everyone should read, Douglas Adams' understood people and his commentary on society is subtle, hilarious yet very deep at the same time.