The new iMac range is coming out in the next week or so. They will not have optical drives built in. They will be thin. They will be more powerful. They will be roughly the same price as the old ones.
Does it bother you that there will be no optical drive? Should you have to buy an external drive so you can either import or export media to/from discs?
Personally, the lack of optical drive in the forthcoming iMac range is the reason I leapt into the recent purchase of the "old model". No optical drive was a deal breaker for me.