Here's what I'm looking to do:

Network two houses, no LOS (trees). Basically I'd like to bounce down to a garage, then up to the second house.

The garage is close enough to both houses that a G router has enough juice to get signal at both houses. WDS over hacked Linksys 54G works fine, but obviously a consumer G router isn't going to last through summer and winter temps very long.

There might be point to point that could bore through the trees (house to house is maybe 500ft at most). Most point to point I find though is commercial stuff in the $2K and up range. Nope, don't want that.

Trying to avoid running ethernet cable down to the garage to an AP, but that's also an option depending on how expensive the point to point options get.

I tried a bunch of commercial antennas to beef up the signal on an Airport and they didn't do squat. There is always the Pringles Cantenna

If you do find something that actually works please post. While you are at it find a cell phone booster too. I am still screwed living in a house hidden by Cape made of granite. The cell signal is touching the top of the house but no go downstairs. I need a n attic booster to spray it down into the house. Again, there are lots of things on the market but I haven't found anything that works.

I have had luck with commercial antennas that boost to 7dbi, but I have not used one over the distance you want. The Pringles can is probably the best bet since it's directional. Have you tried the new Airport/Express base stations, they have a really great range. If you have to operate in temp extremes though I don't know about that.

There are solutions for the cell signal, but since you're a cheap bastard this is probably too expensive.

I'm probably going to go with this:

EnGenius 2610

True ethernet bridge in outdoor antenna panels, and only $180 for two! Sweet!

Says LOS, but 600MW power might be just enough to bore through the trees at the short distance I'm looking at. In any case I could probably mount them up on the TV antennas.

Getting them properly aligned is the challenge.

As long as they're pointing in the general direction of each other, it should be fine. If the signal meters work anything like the skypilot I have for 'net access, it's braindead simple.

We had some at a lumber yard that I worked at that had very narrow signals. They had to be very closely aligned, but they were meant for corporate data security too.

Interestingly enough, the product info for these says you can use one as a repeater, though I wonder how practical that is if these antennas are directional.

I am a cheap bastard but I can put it on my business expense and not pay a dime. But the reviews on those things are pretty dicey. If they had one that for sure worked on grabbing a signal from a tower four miles away, grab that signal in my attic and bend it down into my house I'm all in. The third one on that list seems to be the ticket but everyone is ragging on it. But the one guy who says it is great is mimicking my situation so I guess I will try it.