It depends on how good your line is if you have a perfect line then at 50mbps you'll have downloads of about 6mb/s and at 2mbps upload you'll get about 256kb/s
That is however if you get a perfect line, i have a 50meg line but it constantly varies from 20 to 45ish so it could vary. you might have to do some research around your area to see what others are getting and ask them what sort of speed they say you shoudl get