MBP 2011 RAM upgrade question

I was thinking of upgrading the memory on my 2011 MacBook Pro. The current specifications are as follows:

• RAM: 4GB DDR3 1333MHz
• HDD: 320GB @5400rpm
• OS X 10.7.3 Combined Update
• 2.3GHz Intel Core i5 2410

I want to upgrade to 8GB random access memory. Would this be beneficial? I use my computer for video editing, minor photo editing, web browsing, and documents / presentations. Also, I read in another discussion that adding more RAM can slow down boot time. That person had a 2009 MacBook Pro with 2 GB RAM. It had something to do with having to load more memory on startup. Would this apply to my Mac as well?

And if I upgrade this RAM, what brands are recommended. I was looking at Other World Computing. http://bit.ly/jLmtJK

Thanks for reading - I appreciate your comments.