cost of operating training aircraft?

[LivestockTony]

Hi,

I'm thinking that owning a IFR trainer for about six months and putting about 150 hrs on it will come out much cheaper than renting. I'm trying to put together a spreadsheet, so I'm looking for approximate direct cost per hour of operating:
C-172
C-150/152
PA-28-140 (Warrior)
Piper Tomahawk
AA-1 (Grumman Yankee)

Exclusive of tie down, financing, and insurance (these I have a handle on).

Thanks,
-T
(If I'm wrong in thinking that 100-200 hours on an already high time trainer aircraft won't materially affect the resale value, please let me know!)