The pricing is usually a good indicator (although not every time).
For everyday computing, Intel HD Graphics should be enough - or some other, onboard graphics card like Geforce 7025, Radeon HD3000 series, Radeon HD4250, etc. You shouldn't be looking at something in the GTX 550 Ti/GTX 560 price range for everyday computing. You should be looking at the idle power sausage instead.
But what happens if you don't want to block the one of the slot with the 560Ti wouldn't the 550Ti the only choice?