Tensioner - check.
Gaskets - definitely!
Water pump - Thanks, but no thanks.

I'm on the other side of the fence on the preventative water pump change. I've had only one water pump chew itself up on me (in 1985!) over the course of more than 20 years of driving 6 different cars. Moreover, I know two people who preventively put new pumps in that failed within days or months of replacement. I'd rather keep a proven pump in there instead of spending uneccessary money and incurring unnecessary risk on a new one.