A small addition to the other answers to be more complete: although many routers seem to send out packets with a TTL of 255 (for the packets they produce themselves of course, not those they forward!), most operating systems send out packets with much lower initial TTL values:
- Windows uses 128 (since Windows NT 4),
- MacOS X and Linux both use 64
Some systems used to send lower values (e.g. Windows 95 had a default TTL of 32), those values were raised to prevent problems with possibly longer routes... but those systems were definitely able to reach almost any host on the Internet back then. And —although I don't have any proof of this— I'd say that the required number of hops decreased since, because more and more long-distance fibers are installed to carry the traffic.
Also don't forget that the number of hops and the geographical distance don't correlate. Oceans are generally crossed with a single hop (optical repeaters along submarine fibers don't touch the packets, only routers do decrease the TTL). Just did a traceroute from Switzerland to New Zealand: hop #7 is at less than 50 km from where I am, #9 is in California, and #10 is in New Zealand... the intercontinental transit part is generally only a few hops in a route, the rest is mostly reaching an international carrier, and arriving to the destination from it.