Of those 2 Canondales, I would definitely go for the 29er. I can't imagine a situation where a 26er Hardtail would be a better choice unless it's a question of a small rider, which of course is the opposite of your case.
Other than that, I don't have any particular knowledge of the Cannondale you posted. Looks like a fairly typical mix of AL frame with basic-level componentry.
My buddy who is also 6'5" was in your same position late last year. He ended up with a Trek Marlin 6 in XXL, got a good deal on a '14 model before the '15s came out. Maybe another choice for you to check out.