Why do people sell like stupid? Just because the price is comming to 30 usd?? There is no barrier... just the one in minds of weak people...
Then let them and take advantage of it if you've got the chance to buy more or just chill and let the market get on with it if you're not intending to do anything in a hurry. Personally having been buying since October I have yet to experience what I'd call a proper sell-off. If this carried on downwards for some distance for some time I think I'd be more confident in subsequent growth because the more this happens the more likely we are to shake off some weak hands, let some 'early adopter money' come into play (for those who had been waiting for the rally to peak before grabbing some $) and have the coin move more cheaply into stronger and newer hands 
On the other hand if you just got some in order to make a BTC-only purchase then buy either quickly or wait! It's not often you'll lose out by holding between exchanging and buying but now is one of those rare occasions.
