What Gmail Labs features do you really use?

I check Gmail Labs regularly to see what new features are available. Sometimes the things one can do with a Gmail account are just silly, like Email Addict. If I need a fifteen minute break from email, I can take one without Gmail's help. There are a few Labs features I find indispensible though, and here is my must-have list:

Tasks

I have been waiting for this for so long! I adopted tasks as soon as it was available. It would be nice if it were always visible like contacts and labels, but I can live with the pop out. Nested task lists let me organize tasks into projects. There is just something satisfying about checking of a completed item.

Right-side chat and Right-side labels

I love distributing the screen real estate because it just makes sense when you are using a wide screen monitor, especially a laptop with a measly 800 vertical pixels.

Default Reply to all

Ugh! How many times have I replied to a group and wondered why only one person responded? Too many. The problem is that I just start typing in the quick reply box and hit send before my brain has time to intervene. Defaulting to reply to all reduces the amount of thinking I have to do.

Text messaging in chat

It seems I always remember what I wanted to tell a friend just after they log out. Sending them a quick text without picking up my phone is just great. Plus it is perfect for getting the last word in an argument.

Title tweaks

I'm really bad about opening way too many tabs. Being able to see exactly what is open with a glance eases my tab confusion.

Google Calendar gadget

Who doesn't want to see their calendar in a short and sweet agenda format when they're emailing and chatting? It is great for quickly checking my appointments before agreeing to a lunch meeting that might run long.

Google Docs gadget

Granted, I don't use Google Docs as efficiently as I should. Even when I'm working in Kubuntu I use Microsoft Office 2007. I am one of those weird people who like the ribbon interface. I also do not like the behavior of the enter button in Google Spreadsheets. Anyway, I frequently write simple how-to docs and share them with my users with Google Docs. Having those quickly available for reference is useful at least once a week.

A pretty slim list considering all that is offered. I like to keep things as simple as I can and still have the functionality I need to get my job done.

What labs feature do you think is too useful to do without?