3 Sisters... no brothers.. I'm the youngest.. AUGH!
The oldest is my Half-Sister, I found out about her existance about 8-10 years ago ( I think, its been a while). I still don't see her as a sister, and I doubt I ever will... she's "My dad's kid" with no feeling or anything attatched. I feel a lot of this is because just how fucked up her family is (marriage and kids), we never bonded and with all that I can't stand about that family.. she's here, but I won't see her as my sister.
Oldest Full Blooded Sister? Until she got married and moved out I just didn't talk with her. PERIOD. Wasn't that I hated her, in fact I tried more times than I can count to fix things between us, but it got to a point where I'd say "Hi!" and she'd give me the equivolent of a "fuck off" (because she'll NEVER say the word "fuck"). I just stopped talking to her. All she did was complain about my lifestyle, even though she would only see me during certain parts of the day (so she saw how I routinely got on my computer after class and had a soda... she's a nurse), and just bitch to me constantly. I was happier than a ... umm.. I don't know but I was extremely happy to see her move out. Now things are better, we get along, but I also think a lot of that is due to the fact that we dont' see each other every day. Ah well, Things are better and I can now say 'Hi' to my sister and get a nice response back. I'm happy with that.
Then comes the "middle child" the sister who is my youngest sister. She has always been called "The Cool One." We have gotten along really awesome our entire life (except for one year, which is an entire story in and of itself). Whenever we got grounded (TV, then Games for me, and phone for her).. We'd spot for each other. "Hey! Parents are pulling in the driveway!" I have yet to hear this as a common thing. I used to think all siblings were cool to each other. After I explained this to some of my friends, they all told me how all of their siblings were QUICK to tell on them. This sister is always more than happy to let me drink, because of which I always have free access to her stash!!

We talk about anything and Everything. I haven't exactly talked description about her sex life... but thats something I dont' think i'll be interested in though, either. Heck, that one year when we didn't get along, by that time (when I was a Sophmore in Highschool), we couldn't get each other in trouble because we knew SO much about each other, that we knew we'd both be in trouble for the rest of our lives. Here let me end this with a perspective. I took a class that she is ALSO in, and there are only 9 people total in the class. Tons of people think that would suck, I think its awesome! (Heh, she made a point to tell me that this hot chick in the room is her friend so that I shouldn't hit on her.

... and that she's married. Side Note: It was obvious as I haven't seen a rock so huge! wow!)