It wasn't all that long ago at all that I was getting this advice.

Open games (1. e4 e5) are probably best right now to learn tactics. I play both sides of the Ruy Lopez for many years. I always played 1.e4 and always responded to it with 1. e5. I'd say you're on the right track there.

Against the Sicilian, I'd also agree that the Open Sicilians are probably best. They tend to be very tactical, so they'll teach you plenty, as well.

Against 1. d4, I'll second the suggestion of the Slav. It's a good positional opening, so you'll get a feel of that style of play, as well. Then, as you improve and are ready to build an opening repertoire, you'll have had a taste of both styles, and may have a feeling of which way you want to go.

That said, don't try to memorize too many lines right now. If you're going to insist on doing any opening study (which, believe me, I know is tempting), don't just mindlessy memorize the lines, try to get an understanding of why the moves are made, and see what they teach you about the position and chess. But, seriously, endgames will help you more. Just  try to stay out of trouble in the opening.

A c6-Sicilian is definitely surreal!  

Anyway, seriously now, based on your level I don't think you should worry much about opening sequences. Just use and experiment a lot with the basic opening principles you have learned from your books (iirc it is Chernev or similar?), e.g.: avoid moving a piece twice in the opening without good reason, etc.

However, if you insist I would suggest 1. d4 d5 and then follow up with what you usually do after 1. e4 e5 (e.g. try to quickly O-O). Against the Sicilian, I would also suggest something similar to 1. e4 e5, e.g.: 1. e4 c5 2. Nf3 Nc6 3. Bc4 (or 3. Bb5) and 4. O-O.

Caveat: these are not necessarily considered as the 'best' responses according to theory, but I think they will work OK for your level. Oh, and there is a never-ending debate about the 'best' responses, not to mention there is a good 3 dozens of them..