When we vacation anywhere we like enough space to have privacy (enough bedrooms important/extra baths a nice bonus but not critical) yet we like the places to have places for people to gather because we're on vacation to be together. Size of the place doesn't matter to me, but enough gathering places with enough comfortable chairs and a room/porch/dining arrangement that encourages people to come together and eat, talk, play games, do puzzles easily is what I look for.
Clean is a must - more important than style -- for me. It shows that the owners are on top of the quality of their place and the experiences of their renters. Enough kitchen equipment is important to me because the convenience and I personally like the aesthetic side of cooking/eating so I like the dining dishes/glasses/etc.,, to look nice - don't have to be new or top quality, but I just want to be able to set a nice table and not have to use beach buckets as serving bowls.
I like extra linens, too, because of the flexibility they offer (e.g., a nice blanket for using while resting on the couch or porch), extra pillows for comfort. And I appreciate it when the sheets, especially the fitted sheets, fit the bed and don't come off while sleeping and when the blankets are good quality (I don't like the old polyester pilled ones from the 80s that are still in some places). Cotton is wonderful...
I love outdoor seating areas, too. As for a pool, we have a community pool at our rentals and we love it because it's very big (we couldn't have such a big one if it was a private pool) and someone else takes care of it and we spread the cost of taking care of it among several owners. And pools from what I hear are high maintenance.
Quiet in general is important to me - whether it's inside (relatively quiet appliances which is a challenge) or outside (cars, people, etc.).
Games, puzzles, deck of cards, books, beach chairs - anything that says "we care about your vacation" and things to do and space to do them in on a rainy day means a lot to me. Beach chairs are nice for a lot of reasons and you don't have to worry about always saving a seat at the pool because you can bring your own chairs if needed (and I really like beach chairs that recline).
Parking close to the place for bringing in luggage and bags of groceries is helpful. Close to beach, too.
Ah, and directions for how to use things like the dvd player, etc. We were in Italy vacationing in a great apartment but it took me forever to figure out how to use the washing machine and to figure out how to manage recycling and trash. (By the way, I told the guy who owns the apartment about how wonderful SoWal is as a place to buy and will be sending him more information...)
Wireless is a plus, or a note where I can find inexpensive wireless (e.g., coffee shop) very closeby is important. I can go on more vacations if I'm able to get wireless because I can do whatever work I need to do - even if it's just checking in to make sure all's well or respond to a few emails - and sometimes I use it to stay in touch with family or to find resources where i'm vacationing.
A telephone and phone book, too - these aren't guaranteed in rentals anymore because the assumption is that everyone has a cell phone.