Android users, I present to you—in no particular order—five (out of 10 total) of the finest, most convenient applications I've encountered.

Tripit (FREE) This travel app has become essential to me, in keeping my itineraries at the ready, as well as providing instant access to any trip planning information I may need on the go.

Tripit is awesome, although I blame it for making me miss a flight once, because I was looking at the wrong time zone. Now that I've got the hang of it and I've been traveling a lot more lately, this tool is great for keeping all the hotels, cars, and airlines straight. Combined with, which tracks all of the different mileage and loyalty programs and lets you move points around between them all, this app really makes life a lot easier.

Google Sky Map (FREE) By pointing my phone at the sky, this app really nicely displays and identifies the stars, planets, constellations and other celestial bodies. Great on a cloudless night.

Are you wondering what the stars beneath your feet on the other side of the planet look like? Skymap knows and will show you. Can't remember the name of the constellation you see above you? Skymap knows the answer. Very cool.

Latitude (FREE) This actually comes standard on Androids with the Maps app, but deserves a spot in this list. From Maps, click the Menu button and then Join Latitude. It lets me connect with friends, see their locations in real-time, and adjust what level of details I share with each of them.

My friend Nate and I stalk each other on Latitude. Sometimes I just show up wherever he is having coffee and say hi. I can see how people might find this creepy. That's because it is. But at the same time, if I want to go get a beer with Nate, I can check where he is on Latitude. If he's in another city (he travels even more than I do), then I don't have to bother with the communication chore only to reach a dead end.

Tweetdeck (FREE) This ridiculously convenient app combines Twitter, Facebook, Buzz, and Foursquare. I can sign into any of them and receive updates in one convenient overview. I can update all my networks individually or send the same update to some or all of them.

In my speeches on Web 2.0, I frequently tout Tweetdeck as the best solution out there to the "who has time for all this social media crap, anyway" complaint. The reality is that, whether you are participating in the social media juggernaut or not, the conversation is going on with or without you. If it's a data stream about something you might find relevant, your company, your family, your project, your life, then maybe you ought to get involved, hmm?

Tweetdeck makes this possible (with searches, et cetera) by giving you an ongoing view into the stream of global consciousness around a variety of topics simultaneously—topics that you select—on a variety of channels, such as Twitter, Facebook, and LinkedIn.

Google Voice (FREE) My favorite thing about this app is the instant email I receive when someone leaves me a voicemail. The email translates the speech to text pretty accurately, which is something that Google's been working on lately.

When my mom calls and leaves a message, Google transliterates it perfectly into the written word. My dad is a bit more of a mushmouth though, and I end up having to listen to his recorded voicemail. But in most cases with most people, you can just read the voicemail in your email, which means you can respond to voicemails silently in a quiet place without disturbing people, or similarly, in a noisy environment where you couldn't hear or call back well anyway.

These are only five of my favorite, most useful apps.  There are more to come, but in the meantime, do you agree with my thoughts on these?  What apps have I not mentioned that you think should be on this list?