You can also set up a rain collection center with a tarp and a screen to filter out solid stuff that falls in. Just suspend the tarp over a collection bin or barrel, cut a hole in the middle (well, you might want to do that first, lol...), and cover the hole with the screen. The tarp will allow for more area to collect water, and will work like a funnel to pour the water into the barrel.
40g breeder tanks are one of my faves to. I've recently set up a 75g, and I'm REALLY liking that size as well; it has similar proportions to the 40g breeders.
I think that piece of driftwood on the left would look great horizontal. If it doesn't fit to your liking, you can always cut it. I had pretty much all of my wood pieces vertical like in your pictures when they were in my 28g bowfront, but when we were filling the 75g, they fell over, and my husband and I really liked the way they fell. It looks really natural, and when I get more plants in there and they fill in, it will look like a partially buried log.
Can't wait to see what you decide for the wood.