Hi, went to Rhodes the last two weeks in August last year and it was great - much better than I was expecting, so much so I'm off again on Wednesday (tho' only for 7 days this time - boo). The only problems we had were with one Dutch family at apartments who were evil and shouted at everyone, and at the water park, where predictably the only people queuing were the British.
It's good value in Rhodes, food and drink quite cheap.
Take plenty of sun block - it will be hot and sunny. Also mozzie repellent for the evenings - spray on stuff and for the room as they have a vicious bite. Some resorts have shingle beaches so beach shoes are a must.
Which resort in Rhodes and for how long?