On Tuesday we asked for your favorite instant messaging applications, and over 550 comments later, we’ve culled it down to the most popular five. From web-based chat to desktop clients to tools that combine IM, email, and social networking, your nominations spanned a wide range of instant messaging applications. Let’s take a closer look at the five most voted-for apps, and face them off against each other in a final showdown to crown the ultimate favorite.

Digsby (Windows)

The youngest application by far to make the Hive Five, Digsby has taken the world by storm since we first mentioned it in February. Boasting integration with all of your IM networks as well as your email and social networking (Facebook and MySpace included), Digsby is converting new users left and right with their simple but appealing formula: IM + Email + Social Networking = Digsby. Currently a Windows only app, Digsby’s developers promise that Mac and Linux versions are in the oven—and that they’re constantly squashing bugs from the still-young Windows version.

Pidgin (Windows/Linux)

Formerly known as Gaim, this cross-platform, open source IM client has a huge following on both Windows and Linux platforms, estimating over 3 million users in 2007. Much like Firefox, Pidgin is open and extensible, meaning you can add your own improved functionality and tools to Pidgin by simply installing a plug-in (like one of these 10 must-have Pidgin plug-ins.)

Meebo (Web)

By far the most popular web-based chat application, Meebo boasts support for all popular chat networks, video and voice chat, and even an iPhone interface. Meebo’s main appeal is that it works wherever you are, no matter what operating system you’re using, as long as you’ve got a web browser and an internet connection. Can’t go wrong with that.

Adium (Mac OS X)

The overwhelming favorite chat app for OS X, Adium puts Apple’s default IM application, iChat, to shame. Like Pidgin, Adium is highly customizable, extensible with plug-ins, and works across all your favorite IM networks. In fact, Adium is kind of like a brother from a different mother to Pidgin; it got its brain from Pidgin’s daddy, libpurple, but its looks straight from the dangerous maiden that is OS X.

Trillian (Windows)

Once an overwhelming favorite for cross-network instant messaging, Trillian has lost a lot of users to newer apps like Digsby or fresher ones like Pidgin. That said, the long-awaited update to Trillian, Trillian Astra, is still in alpha, and those who have tried it continue to place all of their IM trust to Trillian. In the future, Trillian is also promising a Mac release along with an iPhone version, so it may have plenty of life in it yet.

Now let’s see if we can’t crown a favorite.

Honorable mention goes to Miranda IM and Google Talk/Google Chat, both of which barely missed the cut.

Whether or not your chat app of choice made the top five, let’s hear what you love about it in the comments.