i went to marmaris last year, and it was fantastic.  I went with my 2 children 2 boys aged 14 and 15,
they enjoyed it as much as i did, belive it or not it was the first time id ever been abroard. 
We went scuba diving(but i couldent do it) the kids loved it.
we went on the four island trip fantastic, jeep safari even better.  What we did was we looked around the first week and booked our trips for the second week, i found out the cheapest place to book and i booked all the trips in one go.  The kids enjoyed every minute but i wouldent take very young kids there its not for very small children.  The atmosphere is fantastic everyone is very polite, i didnt like turkish delight until i went there its deliciouse, as for the shopping its a bargain everything you buy, we were loaded up with lots of presents and souveniers i had to buy an extra holdhall for all the extra stuff, the kids went mad all the addidas clothing 5 shits for a tenner not bad, jeans all top brands 5 pair for twenty quid, should i keep going they bought all sorts of clothing and souveniers.
im going back in september 2002 with my partner and our friends a married couple who have never been abroard before.  I was very nervouse about going abroard for the first time but i shouldent have the people are very nice you dont see ant trouble anywhere, its a very safe place to go.
if you would like any info just ask me see if i can help or maybe your going same time as us and we could meet up

marmaris is a fantastic place to go for anyone