If you don't want to spend any money your combination of drives is a good one. The only thing the Optiarc 7241S brings to the table your 7240S doesn't is the 7241 has LightScribe. Everything else is the same.
Lite-On drives are arguably the best scanners today. The Optiarc drives can scan, but they don't scan for as many variables the Lite-On drives do & the only other drives that could scan well, BenQ drives, have disappeared from the market.
You may be able to cut your two optical drives down to one if you like what the forum is saying about the new Lite-On IHASx24 drives. They are turning out to be very good readers, burners, and scanners all in one drive. And as an added bonus, with SmartBurn those drives will burn Taiyo Yuden TG02 professional media at 16x.
The only warning about the IHASx24 drives right now is that you have to be careful when you buy. Half of them are just re-badged Optiarcs rather than true-blue Lite-On drives.