actually, it's not too important to learn a lot of variations. Have a general idea of what options can occur and have a line for each. Books like Modern Chess Openings have all the openings and provide sufficient coverage of variations for you to get by. It's not necessary to play the latest theory; as Lajos Portisch put it, openings are a means to reach playable positions. As always, more benefit is to be had studying the other phases of the game until you reach a higher playing level and meet opponents where a deeper knowlegde of opening theory starts to become important.
Openings - a minor player`s chaos

Learning various different opening systems will certainly help you improve as a player as you get experienced in different types of positions. However, that doesn't mean you actually have to play all those openings you learn, which means you ought to select some simple starting opening repertoire. Don't chose the most critical theoretical lines, choose something like Vienna or the closed Sicilian instead:
1.e4 e5 2.Nc3 (or 1.e4 e5 2.d4)
1.e4 c5 2.Nc3
and you will get to enjoy the game more.
ps. on the subject of memory.
English Grandmaster John Nunn used to play the sharpest lines, where theory would go into moves 20+. He related in one of his instructional books that he could remember the theory from constant exposure to the material he was looking at. He didn't sit with a book and memorise it cold in one day. I'm not sure what process is at work, a teacher will be able to explain, yet active work with material is good even for those of us with bad memories -- trust me, you are not alone there!

Thanx for your hints. Will help much and is much appreciated.
You saved me from getting back playing useless egoshooters on PC ;-)

My advice is to quit playing e4 alltogether
puting aside your italian game for the moment you are going to be
required to learn tons of theory just to handle the sicilian defense alone,
also the caro cann and the petroff defense, plus to play the
italian game well, you will need to have a good knowledge of the open
games as that will usually transpose into something else, this headache
is the reason i gave up e4 years ago, I used to love playing the kings
gambit and bishops opening, but you only get to go into those lines
maybe 25-30 % of the time because people play all that other stuff.
Hi chessers,
after years of pausing playing chess a just started to get a new approach. So I studied openings, decided to dig deeper mindwise into one which could suit me (the Italian). Several books I read recommend to choose one special opening and study it and then play it for getting used to it forever...
What horrifies me is that all is very neat and funny if your opponent (in my case: chessmaster) follows your initial turns of an opening. But mostly and logically the opponent will decide not to follow the turns of opening books and what you intented in `battling for the middle`.
So ideally one has to know exactly how to modify the inital opening approach if one sees that the opponent does not react to 1.e4 with e5 (e.g. for the Italian). And because of that you have to have tons of combinations in your mind for answering if your opponent plays `apart from the expected`.
That is what scares me in my development of playing I am in at the moment. I love chess for its philosophy and all - but it will always be impossible for my to study, learn and memorize tons of variations. Don`t get me wrong: I do not want to become a GM. I just want to have fun with the game, would like to play online some day without getting destroyed all the time and not in beginner rooms for the rest of my life. And I would describe me as a guy who is keen on learning new things which are complex and dense - but I am weak at memorizing stuff, maybe a flaw in my mind system...
Any suggestions/experiences what could be next steps for me by dealing with openings ?