Here's a website everyone should be using..... be wary of being "sold" on some stock or another on sites like this.... but many sites have great "tools" which a guy can use from time to time.
This will show you the POWER of DRIP (dividend reinvestment) investing... so if you put in a symbol --- and just choose a time frame (say --- 2003 start and 2013 ending - which is a 10 year period) --- and this will come up with TWO CHARTS.... one (the top) showing you DRIP investing..... the bottom will show you without reinvesting the dividend.
IF you are still 10+ years from retirement..... I'd suggest you check the box that says to reinvest the dividends!
http://www.dividendchannel.com/drip-returns-calculator/