I'd agree with the other guys. If you like portrait work then a speedlight is a great accessory to have.


Light stands are really cheap (3m air cushioned stands can go for as little as $40-$50) and umbrellas (also very cheap) are a great way to start off and get to learn the basics. I don't own the 7D so I'm not sure how the flash trigger works but I assume it works off the on-camera flash, triggering the speedlight. I'd suggest a wireless/ radio trigger for the speedlight. I did a bit of a writeup on the Yongno RF-602 ( http://community.the-digital-picture.com/forums/p/3441/28509.aspx#28509) triggers that you might be interested in. I still use these by the way and have had no issues at all.


Hope this helps, Ben