I'm getting more confused on where to go the more I read here. I can't decide where I want to spend my 8 days this July.
I am flying into Miami and flying out of Ft. Laud. I was thinking of taking the shuttle from Miami to Ft. Laud)

(I have no intentions of staying in Miami, just coudln't get a flight direct with my miles)
I'm 38 and single female traveling solo. I thought of spending the whole time in Fort lauderdale and I thought of staying at Beach Harbor Marriott. A friend who lives in Boca suggested that I may want to check out Delray beach or Palm beach.
What I'm looking for is definitely beach time/pool time at a resort but I want to be able to mingle with other singles, explore shops, boutiques and fun hangouts to eat or coffee. At night I'm not interested in hitting the clubs with the 2o-something crowd. Something a little older more sophisticated but fun- wine bars a salsa club perhaps
I could split the time between 2 places but I wanted to avoid having to have a rental car but if it is better to go that route and get a rental than I'll do it. Looking for any suggestions. I'm very active and energetic so I don't mind exploring or walking

In July, the most comfortable place to be is at the beach, so your plan for the beach Marriot is good. We have a wonderful So. Fla. train system that goes from Miami to West Palm and all the stops in between, that includes shuttle bus to all the cities your friend mentioned. It has wackenhut security officers on every train, the fare is around $5.00 and can get you anywhere between Miami and Palm Beach - check it out- tri-rail.com for schedule.
Delray is quite touristy, lots of shops, restaurants, and a wonderful beach. You could bring a bathing suit , shop, tour, beach and eat all in the same trip. Palm Beach has about the same, just not as easy to see all. Miami has the Sea Aquarium, science museum, Coconut grove, South Beach, the zoo, all accesible by tri-rail, Ft. Lauderdale has Las Olas Blvd lots of flea markets, etc. Sounds like a good trip - enjoy.

sounds like I should look into the train system. I'm guessing taxiing it to and from the train might be cheaper than having the car for the whole week. thanks for the input

Check out the Mariott in Delray...it'd be alot easier with a rental car...even just a compact to explore some of the other places you've mentioned.

I wouldn't say that Tri-Rail is a "wonderful" train service on par to say a real subway/commuter rail system. It's great if you're going somewhere specific that it serves, but IMO is not very "user friendly" to eliminate a car and see parts of So. Fla.

I agree with earlier post.. Marriot on Delray Beach is really nice. Over all Delray Beach has everything that you are looking for.. it has fun, sun, shopping, music etc. Yet it is not full of club goer 20 something crowd.

I would personally suggest splitting the time between Fort Lauderdale and Delray since they both have different vibe (fort lauderdale being more hip, young and full of youngsters).

I also wouldn't recommend relying on public transport at all.. specially since you are flying into Miami. The system is not that great, and to get to the beach you will need to get to train than transfer to bus... lot of hassle. Rent a small car instead!