I remember, as a teenager, trying to figure out where I would want to live. This was before I became religious and decided I wanted to make aliyah, so the Jewishness of the location wasn't so important to me. Then I got involved with NCSY in tenth grade. I went on one of their Israel summer programs, Michlelet, the summer after tenth grade. That was a huge turning point in my life. During the program, I decided to become religious, so I knew I'd be changing my lifestyle. Not only that, but it was during this program that I decided that I wanted to make aliyah. I remember being inspired by a Chaim David song that includes a string quartet whose members had made aliyah from the four corners of the world. I suddenly realized that Jews were coming from all over the world and that Israel is the one place where you can really live Jewishly, in a completely Jewish environment.
At that point, I had basically emotional reasons for wanting to make aliyah. That changed when I went to Orot for seminary: in classes like Torat Eretz Yisrael, I learned the religious sources and reasons to make aliyah. I'd always been Zionistic, but when I got to Orot I discovered the meaning of religious Zionism. I realized that optimal mitzvah performance can only occur in Israel. I realized that the Zionist dream of reclaiming and rebuilding the land that has come true and continues to unfold is part of the geula process, and therefore we have an obligation to do whatever we can to support Israel. And the fact that so many Jews are making aliyah is the promised kibbutz galuyot. So, it seems to me that Mashiach is coming soon. Also, so many things about Israel are holy: lashon hakodesh, shekel hakodesh, tzivot Hashem (although the Chabad have a different definition for that).
My children will be Israeli. They will grow up speaking Hebrew and therefore be able to learn Judaism in its original language more easily. They will grow up not surrounded by a non-Jewish culture, and so they won't be jealous that they don't have a Christmas tree. They'll be able to make friends with all the kids in the neighborhood and know they're all Jewish. There are a lot more choices for schooling.
And finally, Hashem gave us this land; it is His gift to us. It was taken away for awhile, but now we have it back. How can I take it for granted? You can go on a tiyul and learn about incidents in the Tanach that happened in that place. The whole land is full of kedusha. It's amazing that the desert is blooming, and it's clearly a miracle. Prophecies are being fulfilled in our generation! How can I not be a part of it?
If I keep thinking about it, I can come up with more reasons. This is very important to me.