Whether you got a shiny new flash drive over the holidays or your old thumb drive is looking for a new lease on life, pack it full of goodness with these five killer portable applications.

Earlier this week we asked you to share which programs you've stashed on your thumb drive that you can't live without. The votes have been tallied, and now we're back with the five most popular portable apps.

Portable Firefox

Lifehacker readers love their Firefox, and with Portable Firefox, you can take your web browsing experience and all of the accompanying tweaks and extensions you've come to know and love with you wherever you go. All of your customizations—including extensions, bookmarks, and configuration file edits—can be applied to the portable version. Minor changes under the hood of Portable Firefox make it more suitable for flash drive usage, such as the default disabling of read/write intensive disk caching. It also respects its boundaries as a portable application, forgoing the usual check to make sure it is the default browser. After you download a copy of Firefox portable, make sure to enable Flash support, customize your portable Firefox, and learn how to sync your Firefox installations.

KeePass

Using the same tired password for everything is a big security risk and so last century. KeePass is an excellent password-management tool—in fact, it topped the list of the five best password managers—and is naturally portable, requiring no modifications to live on your thumb drive. Beyond its primary function of securely organizing and storing your passwords, it also has a host of handy features, like secure password generation—even HAL wouldn't guess the password for your Match.com account is $s2k230!nE$g^8GD@gNygh(hFod0*2E. KeePass also supports great plugins that do everything from automatically filling in password fields for you to importing your login information from other applications like Firefox.

VLC Portable

VLC is an open-source and cross-platform media player packed with features. Even if you never used it for anything more than enjoying some media saved on your flash drive, you'd be quite pleased. Beyond basic media playback, VLC can play ripped DVDs, stream media, and fix desynchronized video and audio. If you're curious whether or not VLC will playback the media you throw at it, check out the sizable list of compatible formats it supports; you'll be hard pressed to find something you can't watch with VLC.

TrueCrypt

Although hindered by the pesky need for administrative privilege or a prior installation on the computer in question—TrueCrypt has to load a device driver for it's on-the-fly encryption and decryption—TrueCrypt remains a reader favorite for thumb drives. In areas where you control the computers or have a friendly local administrator, it's tough to beat the privacy benefits of TrueCrypt. TrueCrypt creates encrypted file containers that function as independent disk volumes. You could easily create a 2GB container on your 4GB flash drive and stash all your private data in it so that—in the event that you lost your thumb drive—no one could access your personal data. Programs and media can all be loaded from the container—once you supply the password and mount it of course—just like they can be from the unencrypted portion of the flash drive. For a more thorough overview of how TrueCrypt works and how to use it, check out Gina's previous guide to encrypting your data with TrueCrypt.

Portable Thunderbird

While many users get their email fix through of a combination of Firefox Portable and a web-based email service, many of you put in a passionate vote for Thunderbird as a portable email solution. Portable Thunderbird has all the features you'd expect from a standalone email client. It supports IMAP and POP3 servers, has tabbed message browsing, advanced folder management, and the kind of extensibility that everyone has come to love in its sibling Firefox. Short of having to comply with the whims of some mad corporate-IT-manager, most users will have a hard time finding reasons not to use Portable Thunderbird for their stand alone mail-application needs. After downloading Thunderbird, be sure to check out our roundup of eight killer Thunderbird extensions, how to embed a web page—such as a TiddlyWiki—in Thunderbird, and how to sync your Pocket PC with Thunderbird.

Now that you've seen the, interestingly enough, entirely open-source list of most loved applications it's time to vote for your favorite:

Whether or not your favorite program made the list this week, we'd love to hear about the portable programs that make your life easier. Sound off in the comments and share the portable app wealth with your fellow readers.