We've been to GC twice. First time we rented a car through
www.grandcaymancruiseexcursions.com. It was great. We rented the cheapest car for the day ($43 incl ins). They pick you up at the blue iguana which is like 3 blocks to the right of the pier. They drive you to their airport location (10 minutes) and you are in an out in a jiffy. Luckily for us, everyone rushed off the van to "get their car" that we were last in line....and boohoo, they were out of the cheapest car, so we got a free upgrade to a jeep! Awesome!
We decided to do the east side tour and get away from the crowds. We drove past the blowholes, the wreck of 10 sails, and saw some absolutely gorgeous mansions/condos all along the way...and ended up at Rum Point. Now, this place is what those corona beach commercials show you. Tons of beach chairs and no chair hogs! Lots of little stores all around. An outdoor cafe. Nice bathrooms/showers. There is also the red sail sports desk. There we booked a 2 hour tour on a glass bottom boat out to stingray sandbar. The sandbar is actually closer to rum point than where the ships dock in georgetown so it only takes 15 minutes to get there instead of 45. LOVED IT!
That was in Jan 04. After Hurricane Ivan swept through, GC has had a shortage of cars. We tried to get one for our Jan 05 visit, and none were available....so we opted to take a cab to SeaGrape Beach for the day. It was a very nice beach as well, but busier than Rum Point. You still could see a lot of the damage from the hurricane, but the beaches/water are still awesome. And, the locals are ever so friendly.
The way I look at it, you can't go wrong on Grand Cayman. Its a gorgeous island. I want to go back!