I am trying to learn how photos work on the iDevices and with iPhoto and whether it will be useful for me. I am trying to learn other apps as well (PhotoMgrPro, Photosmith) to see the relationships between them and iTunes/iPhotos.
Since you are using a MBA, I'm guessing you are syncing with iPhoto, and it sounds like you are syncing the entire library. I can't help much with this. My iPhoto library is much too big and chaotic for me to sync the entire thing on my little 16GB iPad. I only sync selected albums.
If your main problem is finding specific pictures that you want, I recommend making some albums in iPhoto, and/or some creative management of your Events (which you can choose to sync in the iTunes settings). If you take the time to tag your photos with some keywords, you can even create smart albums to do half the work of sorting for you.