Assuming my family and pets got out... I don't know. Probably my wallet, cell phone, and car keys. That'd be easy since they're almost always on my person or directly beside me. Probably my laptop.
Used to be I'd say my artwork, or maybe my art supplies. But I think I could leave those, now. I do have things of sentimental value that I can't seem to bring myself to throw out, but if circumstances led to them being destroyed, or disappearing... I think I'd be okay with it.
Edit Like most sane people living in a hurricane-prone area, I generally keep a bag containing several week's worth of medication and a change or two of clothes + some toiletries around. During hurricane season, it's in my room with me, the rest of the time it's generally in my car (which is where it lived when I was in San Antonio and driving around a lot). My key stretchy-bracelet-thing also has two flash drives on it, with all my important documents and school work backed up on them, so even if I didn't grab my laptop, I'd still have any files I'm likely to need.
My mother might have some important documents stashed away in the house somewhere; I'd have to ask her where so I could grab them (since she can't carry much).