A couple days ago, Leslie wrote about the ten websites and apps that she uses daily. I enjoy getting a peek into how tech workers “do their thing,” and Leslie’s article was no exception. In fact, it inspired me to share my own list.

1. Twitter Yes, Leslie mentioned Twitter, but I couldn’t omit it from my own list. While including Twitter was a given, explaining exactly what Twitter is — and does — is not as easy. To that end, I’ll share three stories that explain how I’ve used Twitter.

I spend most of my time working alone.  I love the quiet and solitude, but sometimes I miss the idle banter that enlivens many busy office buildings. For me, Twitter is the “water cooler talk” of the internet. “How about those Red Sox?” “Did anyone watch Survivor last night?” “What’s the best vanilla ice cream I can possibly buy?”

In this example, Twitter is a comfort thing. It’s like having your friends around. You can respond or not; share or continue to work quietly.

I’ve also had Twitter succeed where Google has failed. Recently, I was stuck on a task I was trying to pull off with WordPress. A fifteen-minute Google search yielded poor results, but five minutes after posting the quandry to my Twitter followers, I had the exact answer I was looking for.

I’ve replicated this twice now. I work in the tech industry, as do many of my followers. So, asking a technology question to those 600+ people is likely to yield a positive result. In some instances, Twitter makes a darn good, human-powered search engine.

Twitter has also been a great networking tool for me. In the past six months, I’ve made great friends, business contacts and gotten paying gigs all because of Twitter.

What all of this comes down to is communication. Twitter is a very contemporary communication tool. Now, if I had described Twitter as “this website that allows you to share little messages with other people while reading theirs,” you would have brushed it off as nonsense. However, as I’ve demonstrated, it’s much more.

I should note that I don’t use Twitter’s web interface. While working on my computer, I use Twitterrific, and Hahlo while on my iPhone.

2. Freshbooks I’ve been using Freshbooks for client and invoice management for months now, and I love it. It’s easy to create, edit and send invoices (via email or paper mail), monitor what’s been paid and what’s outstanding, track time spent on a project and more.

There’s a great Dashboard widget for Mac OS X and it even integrates nicely with Basecamp. The support folks are responsive and the customization options let you create a real professional look. Freshbooks definitely offers a lot for the small monthly fee.

3. Imagewell I spend a lot of time writing and blogging. The process is much more pleasant because of ImageWell. Every post I write for TUAW must be accompanied by an image, with a maximum width of 225px. So I spend a lot of time cropping and resizing images. Now, applications like Photoshop are overkill for such a simple task. Why would I lauch a behemoth of an app to perform such a simple procedure? It’s like swatting a fly with a Buick.

For me, ImageWell is the answer. It’s very lightweight with a simple UI. I can do what I need to do with a few keystrokes. I can even upload to my iDisk or FTP server with a click. I absolutely love ImageWell and use it every single day, several times.

4. ThinkFree Office This online alternative to Microsoft Office has replaced Word on my computer. Every post I write for Parenting.com begins its life as a ThinkFree file. I can edit it from any computer that’s connected to the internet. No special software necessary. No, “Oh God, I left that on the other computer.” No misplaced email attachments.

There’s a great desktop app that makes synchronization between local and server-side files a snap. Plus, sharing files via a blog is just as easy. They’re even working on an iPhone application. Finally, translation to and from MS Office format is not a problem.

With ThinkFree Office on my side, I have no need for Microsoft’s $300 suite.

5. Backpack What can I say about Backpack that I haven’t said before? For me, paper is the ultimate tool. I know, it sounds crazy, but I’d rather use a notebook and a pencil for almost everything. Paper doesn’t fail to boot, break down, exhitibt compatibility issues, need upgrades or a wall socket. Paper works anywhere — on a plane, a bus, a coal mine, elevator, space shuttle — and costs next to nothing. A blank sheet of paper is pure potential. Plus, a pad of paper is much easier to recycle than a computer.

What does this have to do with Backpack? So many “organizational” applications, like Midnight Inbox, iGTD and countless others try to immitate paper. The developers who write these apps struggle to impart the flexibility and usefulness of paper and pen, and none of them succeed.

However, the one that comes the closest is Backpack.

Backpack eliminates all of the clutter of toolbars, icons and whatnot and offers a blank white page. Just click and start typing. Just like paper. I use Backpack for GTD, storing receipts for tax time, creating Christmas lists and so much more. My Backpack “Inbox” is my browser’s startup page.

If I had to give up one of the applications on this list forever, it would not be Backpack. Heck, take all of the others away. As long as I have my Backpack, I’m good.

6. Mint I run Mint on my websites for traffic analysis. It’s beautiful, useful, dynamic and enhanced by an ever-growing number of plugins (or “peppers”). Sure, it’s $30 and Google Analytics is free, but there’s not beating the usefulness and gorgeous presentation. Plus it looks great on an iPhone.

So there you have it - the applications I cannot live without. What’s on your list?