Hey, sushi is all good! Go with an open mind -- try it all.
Magoro is nice -- raw tuna. People are usually pleasantly surprised by that one. Toro, a more fatty (and more expensive) tuna is really, really nice.
California rolls are okay, but there's no fish in them really. If you only eat California rolls you aren't really eating sushi.
On the other hand, some of the US-only avocado/eel "dragon" rolls or inside-out rolls seriously kick ass. I think it's funny that you can't get them in Japan. Or couldn't the last time I was there. I know, eel sounds gross, but it's cooked, and it's sweet, and it's to die for...
The ones that are more of an acquired taste include octopus, squid, and sea urchin. Save them for later in the meal when you're feeling cocky, or maybe for a second visit.
But try 'em all eventually. It's the only way to find out what you like.
Wyst