What would you use it for? There's no longer a need to install software by disc, most data transfer is done by memory stick, so all that's left really is playing DVDs. If DVDs are used a lot then it's worth having a disc drive but there's little use beyond that.
Agreed, optical drives are only usedul these days for playing dvds. If you need it for that, then you can buy an external optical drive that plugs in via usb. Otherwise, like PPs said, apps are downloaded and flashdrives can be used to backup data - although cloud services are also very good.
RAM - have as much as possible - this affects laptop speed. do not go under 4GB
Memory - if you can get one with Solid State memory (usually abbreviated as SSD), then that is the ultimate, as it make boot up and opening apps/programs and files virtually instantaneous. Do not go for anything under 120GB, as apps and windows can take up huge amounts of space and leave little left for things like pics or video. But, if you plan on storing all your data online, then you can probably get away with less. Hope that helps a bit. I would call the supplier and talk through your needs with them before you order.