I had the same question in my mind since long time . I had both lenses and shooting the D7000 too .
After i bought the 10-17 i had never used again the 10.5 for the only reason of the advantages of having a zoom capabilities on my camera, which can help a lot to change compositions of certains situations/subjects .
I think that the 10.5 is a little bit sharper and produce less chromatic aberration than the 10-17 but the advantage of being a zoom put the 10-17 as my top choice , specially for the kind of wide angle photos that i made most of the time : reefscapes,big animals and caves.
For static subjects , like wrecks i all probably prefer the 10.5 over the 10-17
There are a lot of wonderful sites around Bohol. I have not been there in several years, but I remember that my favorite sites were around Balicasag Island (about a 40 minutes boat ride from Alona Beach). My favorite site in that area was Black Forest. Not much big stuff, but incredibly pretty reef. I also liked the reef-y stuff around Alona Beach.
I second Edpdiver . Balicasag was my favourite .I was there 3 years ago and used Seaquest dive center based at Oasis hotel which I found is ok and very convenient . I also dove other areas at Visayas : Pescador , Apo and Cabilao , the most beautiful scenics was around Balicasag .