Just so people don't have to visit the Webapps FAQ, here are the normal reputation limits:
15 Vote up
15 Flag offensive
50 Leave comments†
100 Edit community wiki posts
125 Vote down (costs 1 rep)
150 Create new tags
200 Reduced advertising
200 Retag questions
250 Vote to close, reopen, or migrate your questions
1000 Show total up and down vote counts
2000 Edit other people's posts
3000 Vote to close, reopen, or migrate any questions
10000 Delete closed questions, access to moderation tools
(The advertising one doesn't apply to SE sites as they don't have advertising yet.)
For what it's worth, I think we're very close to being self-sufficient with respect to being able to close questions. Not counting the current moderators, there are 6 members who already have the necessary 3000, 4 of which I believe are still active, and another 7 members above 2500, so they'll be able to vote to close very soon.
In the meantime, we currently have 6 moderators and most of us check the site very frequently, so if you see a really egregious case but you've lost your close rep, you can always leave a comment and/or flag for moderator attention. Probably by the time we get through formal moderator elections, we'll have at least 20 members with enough reputation to vote to close, and that should be plenty.
The only thing we won't have are the 10k+ users, but I don't see a lot of people using the 10k tools anyway. They're not really that important until the site gets really busy (as in, questions don't stay on the front page for more than an hour or two).
If we do start to run into problems then it is possible to put the site back into "bootstrap mode" where all of the rep limits are lowered, but I would only recommend that as a last resort.
(P.S. I actually think that the tag creation limit should higher for this site, but as long as people are on the ball with retags, then we shouldn't have a big problem.)