Yes , sellers with holding power will hold on , but when stock market is down(potentially lacklustre for 2008) , and inflation is high , holding power will be diminished, and only investors with sound investment strategy, without over exposure to volatile investments will hold out. Thus , do not wait till the market crash and you are forced to cut loss. Plan ahead take some profit while you can. Not everyone can buy at the low and sell and the very peak. In betw, there are also profit to be made.
Then again , it all depends on individual opinion on the market this year and of coz your risk appetite.