Anchor advice?

I want to get an anchor for my 20' Malibu VTX. Been looking at different anchor's on the internet and the box anchor looks like it would work well? By no means am I set on the box anchor, any advice on different anchors would be greatly appreciated. All I want the anchor for is to keep my boat off the beach....This will probably start a whole lot of hate.... Ocasionally I beach my boat! Only at location's where there's a fine sandy bottom, with all ballast totally empty. I would like to be able to drop off family and friend's then anchor my boat off shore. Okanagan lake can get a little rough at times, So the anchor will have to be able to sustain some chop (1'-3') without moving the boat around.