As widely rumored, the new iPad models (one for Verizon and one for AT&T) announced today will offer several varieties of high-speed cellular wireless networking. iPads sold for use with those two carriers, plus Rogers, Bell and Telus in Canada, will work with an alphabet soup of fast connections: the 3G EVDO and HSPA standards (also on the iPad 2) plus the newer HSPA+, DC-HSDPA and LTE standards.
All three of the newer standards are speed demons when compared to the 3G technologies. HSPA+ tops out at a theoretical maximum of 21 Mbps download speeds, and DC-HSDPA can hit a screaming 42 Mbps. Neither of them can stand up to LTE, however, which (in theory) can hit a scary-fast 73 Mbps of downlink speed. If you think the carrier networks are congested now, here's some crystal ball forecasting: wait six months.
Another interesting tidbit about these hyperspeed iPad models is that they will support personal hotspot networking (with carrier approval). You could run a small network of five devices off your iPad's fast connection; that's great news for mobile professionals.