Personally, and despite all the hype, I recommend avoiding Skype like the plague. They use a closed protocol that doesn't play friendly with the other VOIP services. You have already noticed that Skype's charges to landlines aren't all that great, the real kicker is that you miss out on the major advantage of VOIP: being able to phone other VOIP users on other VOIP systems for free.
That may seem to be a secondary consideration right now but just wait for the network effect to kick in; at some point over the next couple of years, most businesses internationally will be using VOIP and listing SIP numbers.
That isn't optimism, it already makes solid financial sense for organisations of a certain size and developments like better commodity hardware and Open Source software like Asterisk is opening it up to ever smaller organisations. Many of the landline numbers you see today merely mask and route to SIP numbers. There's undoubtedly a tipping point on the way when the number of people with VOIP will persuade organisations to list their SIP numbers alongside their regular numbers.
At that point, the argument for VOIP in the home will become "spend $60 on a small box you can stick your existing phone into and every number becomes a toll-free number".
Skype users can only talk to other Skype users or, by paying the comparatively high Skype-Out rates, regular landline and mobile phones. Skype only looks good when you compare it against the traditional telecoms companies. A half-rotted dolphin would look good compared against the traditional telecos.
Skype got the hype because the guys who launched it had some sort of connection with popular P2P app Kazaa. By the time Kazaa was sued into bankruptcy, it's technology had already been superceded by a less proprietory technology, BitTorrent.
It's worth noting that Skype saves the Skype corporation a few cents by using your computer to process other peoples calls, even when you are not making a call yourself. P2P makes sense for getting your hands on pirated music but not, IMHO, for VOIP. I don't see any good arguments for Skype.
A question for those of you currently using VOIP in different countries: is there a big difference in quality in different countries? How is Pattaya?
And does the quality of the actual broadband service make a big difference? I get what has been said about VOIP requiring not that much bandwidth but I suspect that high-contention rates of most consumer broadband products has got to hurt and I've heard that Pattaya's broadband sucks like a wind tunnel in reverse.