Basecamp - Convenient system for project management. Just today I switched to the next tariff plan, now I have a limit on 35 projects, 10GB of space, SSL and Time tracking.
Wufoo - Allows you to quickly and conveniently create forms. It’s better than programming that you don’t need to think about security, it’s convenient to set up notifications (there is even a special desktop program for getting filled out forms).
Dropbox - Synchronizes one of the folders on your computer with the Internet. You can give direct links to files from it. Also, you can give access rights to internal folders to other users - it is convenient to share files at work.
Vimeo - The most convenient video service from those that I found. Simple, beautiful, great video quality.
Google Docs, Google Calendar, Google Reader, Picasa. Links and descriptions will not give, it is strange if you yourself do not know these Google services. They say that Flickr is better than Picasa. Maybe, but I’m already just too lazy to transfer photos there.
What I'm going to use :
Zendesk - Online user support system (tickets). Used, for example, Twitter.
hab.la - Live chat for site visitors with the ability to respond to their messages through jabber.
What I ideologically like but for various reasons is almost never used :
Twitter - Livejournal for lazy nyrds and office plankton. But he has a big plus - you can write there from a mobile phone, via SMS. Read completely once but sometimes I write.
Friendfeed - I don’t use it as I read RSS via Google Reader. But sooner or later I'll start.
Of course, I could forget something, so the list will be supplemented. But since this is a crosspost from my blog , the updates will be there.