What???
You need a TV in any way. Or should I have missed something?
If you meant "new TV", that's also wrong.
You won't need a new TV for HDTV, but it would make sense because of the res/bitrate compared to SDTV.
It's only via SAT so far, but starting up in UK via DVB-T soon.
DVB-T HDTV will never come to Germany i.e., because of the limited badnwith available!
Also, there are HDTV channels already available via DVB-C.
All depends on your local reseller/provider.