Also a basic first aid kit, including duct tape. It's great for all sorts of jobs, including closure of larger wounds.
Good quality LED head torch too
some of the ones from China are pretty good, if you get the right one.
To save buying a new/second sleeping bag, it's worth investing in a fleece liner, or even a good quality silk liner. This should let you use the same bag in slightly colder weather. If you plan on being out a lot in late autumn, winter, early spring, then it will be worth getting a warmer bag (somewhere around -15ºc extreme should be enough).
A 40L dry sack to keep your clothing and sleeping bag in, while inside your pack. Doesn't have to be really heavy material, as it will be protected by the pack, but it will make life more comfortable if you have to leave your pack in the rain while setting up your tent