I think we've had a tonewood poll already but I didn't see a topwood one. Bob Taylor has said that the topwood makes up 90% of the guitar's tone. I'm going by Taylor's BTO sheet. Some people may say: "Well, it depends on what the tonewood is." But just imagine this - if you could only have one guitar for life, and it was a BTO, which topwood would you select (with your tonewood of choice)?
I purchased a 716ce with an Engelmann top because when I was comparing Engelmann to Sitka on an 814ce and an 914ce with those tops (respectively) at the store I found Engelmann was much smoother for fingerpicking. At first I didn't like the compressed sound when I strummed... But then after playing for a few more hours I realised that the Sitka was all over the place, it was like playing a piano with the sustain pedal pressed down the whole time without lifting your foot (that is an extreme example and it was nowhere that bad, but gives you an idea of what I mean).
I've only ever had one experience with an Adirondack top, it was a Collings DS2HA - couldn't stand the absolute lack of sustain - whether or not it was due to the Adirondack top or short scale or just how a Collings sounds I don't know, but it makes me wary of purchasing a guitar with that top without playing it first. I have been tempted to buy the 514CE-WW with it though.
Finally, Cedar. I've loved the sound of Cedar on a 714ce. It actually sounded very good when strummed hard, such beautiful bass response and after playing it in the shop, the 814ce and 614ce and definitely the Fall 2011 Koa GA all sounded weak and sharp in comparison (an OM body all-Mahogany Santa Cruz which I later tried blew its bass response out of the water but that's beside the point). But when I tried it on a 716ce it sounded horrible - far too muddy. The tone, whether strummed or fingerpicked, sounds like something that would be more suitable for rhythm guitar though, like having a bass player in a band to back up the guitarist, in my opinion, hence why if I was only to buy one guitar for solo performances (which is what I usually do), I would not choose this top.