Some PCP's are putting out a shitload of power - Sumatras in .25 can do 900fps. The 9mm Shin Sung is claimed to shoot 77 grain pellets at 900fps - mind you you won't be walking into any old gunshop and asking for pellets for one.
As for springers, the new Sheridan Superstreak is claimed to do 1500fps in .177 (but like most of these sorts of guns probably doesn't....) The big springers are big, long, heavy, hard to cock and can have high recoil, making them hold sensitive and harder to get the hang of shooting accurately - and kill some scopes quick smart too. Springers from the better makes like Weihrauch, Beeman and Diana are less likely to crazily overstate the velocity claims than the Chinese made guns, Gamo's etc.
The gas ram guns like the Beeman RX2 and Theoben guns can churn out a fair bit of power too - over 800fps in .22, coupled with a quick and easy break barrel configuration.
If I could have but one it'd be a gas ram gun as I like break barrels, tend to shoot a lot of shots in a session and prefer a self contained power source rather than air tanks etc. I'd prefer .22 due to the more efficient power delivery and the ease of getting a variety of pellets anywhere.