I've started reading Benjamin Graham's book "The Intelligent Investor" and have been amazed by some of the insights that he had. I'll be starting a new series referencing Mr. Graham and help to share and reinforce his knowledge to everyone else.
On page 191 Graham wrote "There is one aspect of the 'timing' philosophy which seems to have escaped everyone's notice. ... He enjoys an advantage only if by waiting he succeeds in buying later at a sufficiently lower price to offset his loss of dividend income."
This quote from Graham really shed light on the fact that while you might not be getting the best price possible that price might not ever come. And what possible signs are that that without a shadow of a doubt the price will not decline further. You should instead look to purchase shares that with a margin of safety that you're comfortable with and when it hits that point pull the trigger. If you try and time the market you are risking the loss of the dividend income. In other words, if you don't make the purchase and the cash sits idle you have lost the opportunity to receive the dividends.
For example, say you wanted to buy Johnson & Johnson (JNJ) and feel that today's price of around $64.14 represents a good entry price. If you don't purchase the shares because you feel that the market has gotten ahead of itself and continue to wait for a pullback and it takes a year for that pullback to happen you would need the shares to decrease by the amount of the annual dividend, currently $2.28 per share, just to make up for the lost dividends that you should have received.
In conclusion, if through your analysis you find that the current share price represents good value then by all means make the purchase.
I highly recommend reading through The Intelligent Investor if you haven't yet done so.