If you are just looking strictly for SE, I'd say the 7x36, unless you are shooting across big soybean fields etc. But for distances out to a couple of rifle shots distance, the 7x36 is where I'd go. I use the 7x36 and 10x43 ZEN ED 2 as a combination, but the 7x gets 80% of the use even out west in the high desert where I hunt. I simply do not see enough of in image size loss with 7x over 8x that it makes any difference to me. What the 7x does have over the 8x is a deeeper depth of focus and a wider fov, which make a very nice combination to my eye, being preferable to the 8x.
Lots of people like the 10x for distance, but that magnification selection is largely a personal deal and you have to sort that one out for yourself. Personally, if 7x is not enough, 10x only "may be" enough to get more detail, but really I need to go 15-20x with big eyes or a spotter to get enough more over 7-8x to matter much. I prefer the wider view of the lesser magnification, and keep in mind that the more magnification you use the greater the strain on the eyes, so the ability to use a rest or tripod may be useful.