It seems like Maui might be the place for the best blend of vacay and diving. I personally didn't really connect with Kauai, a little to slow for me, and Oahu just feels like a tropical version of Newport Beach which is what I try and get away from when on vacation. The big island was awesome diving but really BIG and we were staying nearly 1/2 hour drive from the harbor where the boats left from (we were in Waikoloa which was very isolated and had a dismal food and shopping scene). I also didn't think there was as good a selection of food and activities in Kona vs Maui overall and we didn't have an extra day to do the whole volcano thing (which takes a whole day at least from Kona and does have an elevation concern after diving).
As far as Maui, diversteve gave lots of good info - for tanks we use MAUI DIVING Scuba Center/Snorkel Shop. Equipment Rental - they are in downtown Lahaina and a very laid back shop with great prices. I don't know about guides up north as we've never used any but Shaka Doug is an excellent guide for the southern area and scubahawk27 does scooter dives out of Makena landing which we also enjoyed.
Between Lahaina and Napili, my fav shore dives are Mala wharf, Black Rock and Old Airport (easy in and out and a reef that goes on and on) we've done these many times and are easy and fun! Black rock for a night dive is always a must for us, and I did a detailed version of how we do it (there are many ways to pull it off, but this is our version)
http://www.scubaboard.com/forums/hawaii/461115-black-rock-maui-night-do-i-need-guide.html
We've done the reef in front of the Hyatt (Canoe beach I believe) which was good for turtles but just so so reef and viz. Slaughterhouse/Honolua bay are excellent sites, but IMHO a real PIA for gear in and out - long hike and/or stairs. We also hit Olawalu which is south of Lahaina at mile marker 14 and really liked that - the reef literally goes on forever and is very shallow so you can make a tank last and last!! The hardest part for us was finding the way back as all the coral looks the same and we missed our channel and had to swim back out to pick up my SMB that I'd tied off. The shore diving site that was posted by diversteve really lays it all out for shore possibilities.
We have used Lahaina divers for trips out to Molokai, and Lanai - big comfy boats, and very organized, leaves later so it's not such a shocker for the morning. We've gone with Prodiver for trips out to Molokini, They leave from Kiehi harbor very early so you are leaving the Lahaina area before dawn to make the boat. Pluses are it's a small boat and if you talk to them in advance, they can set you up to do the back side of Molokini (conditions allowing), and also feature live boat drifts which makes this the most Cozumel like experience we've found in HI. Because they leave so early, you are back with nearly your whole day left for more adventures!!
Have fun!!!
As far as Maui, diversteve gave lots of good info - for tanks we use MAUI DIVING Scuba Center/Snorkel Shop. Equipment Rental - they are in downtown Lahaina and a very laid back shop with great prices. I don't know about guides up north as we've never used any but Shaka Doug is an excellent guide for the southern area and scubahawk27 does scooter dives out of Makena landing which we also enjoyed.
Between Lahaina and Napili, my fav shore dives are Mala wharf, Black Rock and Old Airport (easy in and out and a reef that goes on and on) we've done these many times and are easy and fun! Black rock for a night dive is always a must for us, and I did a detailed version of how we do it (there are many ways to pull it off, but this is our version)
http://www.scubaboard.com/forums/hawaii/461115-black-rock-maui-night-do-i-need-guide.html
We've done the reef in front of the Hyatt (Canoe beach I believe) which was good for turtles but just so so reef and viz. Slaughterhouse/Honolua bay are excellent sites, but IMHO a real PIA for gear in and out - long hike and/or stairs. We also hit Olawalu which is south of Lahaina at mile marker 14 and really liked that - the reef literally goes on forever and is very shallow so you can make a tank last and last!! The hardest part for us was finding the way back as all the coral looks the same and we missed our channel and had to swim back out to pick up my SMB that I'd tied off. The shore diving site that was posted by diversteve really lays it all out for shore possibilities.
We have used Lahaina divers for trips out to Molokai, and Lanai - big comfy boats, and very organized, leaves later so it's not such a shocker for the morning. We've gone with Prodiver for trips out to Molokini, They leave from Kiehi harbor very early so you are leaving the Lahaina area before dawn to make the boat. Pluses are it's a small boat and if you talk to them in advance, they can set you up to do the back side of Molokini (conditions allowing), and also feature live boat drifts which makes this the most Cozumel like experience we've found in HI. Because they leave so early, you are back with nearly your whole day left for more adventures!!
Have fun!!!