One of the ways of combatting self-upvoting is to make it less rewarding than curation. You should be able to upvote your own post if you REALLY believe it is worth it, but the cost of the self upvote should be higher than a regular vote, and should increase with every self vote made in a 24 hour period. Basically it drains your voting power quicker and is capped at a lower percentage the more you vote. Eventually you have no power left to vote and have to wait to recharge.
If you're interested, have a look at my proposal here. It's nearly 2 weeks old now and so outside the payout window, but would like to see something like this implemented. Let me know what you think. It's quite a long read. It also deals with delegated SP and voting bots.
That was a really good proposal @bmj... I like the idea that people can have ONE shot at upvoting themselves at full power... and after that it's pretty much a losing proposition.
Exactly that @denmarkguy. It doesn't take it away, it just makes it less effective the more you use it on yourself.