Finishing with Safari
Right, for some unclear reason I was still browsing with Safari. With 10+ tabs open and some flash content running it turned out that Safari was using 700-800 Mb RAM with large variety of apps running in browser. So switching to Chrome as we speak. Seems memory usage is smaller with it and browsing quicker. Outrageous use of resources by Safari.
Cleared browsing history in Safari and gradually I also get back harddrive space. Tried to quit it but now its just beachballing, probably cleaning after it self right now as free space amount on harddrive is constantly rising.