Here in Finland, most home-use xDSL connections are not capped (And actually in 2002 I did have a uncapped dial-up connection)
Currently I have full rate VDSL2-connection (nominal 100Mbps, in reality about 40M - long land line...)
In 3G/4G connections first ISP (TeliaSonera) launched the usage cap year or two ago, which was received quite harshly among users. Even though it is not a hard cap - after the cap is achived, the connection is in lowest priority (especially during daytime the speed might be very bad) and there is no extra cost if you exceed your cap.
But luckily it is still possible to buy uncapped mobile connections (full 3G (Nominal 21Mbps) is around 15-25â‚¬/month).
For me it is uncomprehensible that first you should purchase a connection with said speed and then not being able to use it after arbitrary limits.
Back to the question - How much I can download with my package?
In 2005 I had a 512k/512k connection, once I did download something like 100+ gigs in a month, which was basically very nearly running the connection at the limit...
2008 I had 4M/2M connection - So theoretical max. download in a month would've been about 1TB.
And now if my current connection keeps that 40M speed, it would yield a theoretical 10TB+ in a month.
The 150GB/month cap would probably be borderline OK, as now my uptime is 94 days and during that time ifconfig says that received bytes and transmitted bytes add up to 536GB (so 179GB/month).
But this is on one computer, if you don't live alone and these times of high definition... No way :disagree:
IMO it's better to have a constant (even slow) speed and not to worry about how many bytes I can still transfer...