Paul, those are a couple good choices indeed. Based on your sig I guess you are off-road a couple times a month at least and I would say you would be better served by the compressor kit. I have the same tires and they are indestructable so I don't think you'd be getting stuck any time soon to require the Hi-Lift.
On the other hand the Hi-Lift is rarely on sale and this gives a good opportunity to pick it up at a reduced cost so it may be more money saved in the long run to get the air kit later (I think they are on sale more often). Don't forget with the Hi-Lift though you'll probably also want to pick up the 'Off Road Base', 'Handle Keeper', and some sort of mounting kit, maybe even a protective cover as well - so it may end up costing you more?
I want to live vicariously though - so get the air kit!