I've been out of computer programming for several years and my skills are no longer current. (I used to be an applications programmer.) What does everyone think would be the best skill set to develop in order to re-enter programming as quickly as possible, and what would be the best (and most cost-effective) way to go about developing those skills? Thanks to anyone who can help me.

Nowadays I would suggest web apps. Since cloud computing is the current buzzword and I don't think distributed computing will be going away anytime soon, learning how to work w/ either browser-based apps directly or, at a minimum, highly Internet-enabled applications will be invaluable.

If you're a Microsoft developer, obviously any .NET language will be good, though C# seems to the be most popular right now. Additionally, C# is cross-platform with the Mono Project. The Express Stuido editions are free but somewhat limited; you may run into the need for the Professional versions, which obviously cost some money, sometimes quite a bit.

If you don't have a preference, then consider Django, which is built on Python, or Ruby on Rails, which is built w/ Ruby. Both are designed for rapid application development and the core languages (Python and Ruby) can be used for programs outside of the Internet. Additionally, they don't cost money and include everything.

In regards to getting up to speed quickly, either recreate an application that already exists or scratch an itch; make something that will make your life better. If you're still stuck, ask friends or family if they have any projects they would like to you create for them.

If you still don't have any ideas, make a video game. The good thing about games is that they incorporate a lot of features that standard business apps don't, so you have to extend your skill set which will help you in the future.