I use Google Apps both personally and professionally.

Personal Use:
I have personal domains, like most of us geeks, and thus I want to be able to receive email at a custom email address. However this usually requires a complicated setup, an email server, and a cost associated with both. Google however provides this service for free and walks you through the setup step by step. It takes only a few minutes and you can setup quite a few email addresses....last check was 10 freebies on your domain.

Professional Use:
I work as an IT person for an advertising agency in NYC. We are currently evaluating Google Apps Premier for our business use vs Microsoft Exchange. Why would we do this? Simple. Google Apps charges $50 per user, per year, for 25gb of email storage. The same scenario on MSFT Exchange would cost us 10-20 times more. Enough said.

Google has also recently released a software that will allow enterprises that use Blackberry Servers to connect to Google Apps and enable full synchronization between the blackberry and Google Apps account.

Google seems to be on the right track with Apps and it seems to be getting better daily. Whether its the free version or the premier version...u will be thrilled at its usability and savings.

My family and I are currently pretty well addicted to Google Apps. I'm in the Army Band (in Japan) and I have a pretty strange performance schedule. To help my wife and I plan our families medical appointments, day trips, and other activities, we've started using the Google Calendar.

Also, for some paperwork, I upload it to Google Docs and and I'm able to view/edit the paperwork anywhere! I have a list of phone number of my co-workers uploaded, and I can pull the list down onto my iPhone, click on a phone number, and the phone will dial it right there! Very convenient!

A big thumbs up in general for Google Docs/Apps/Gmail. They're headed down the right street for family and corporate productivity.

I use Google mostly for personal use.

First is Gmail. I use Gmail to consolidate multiple email accounts not only other Gmail accounts, but Yahoo! Mail, and other email accounts that I have. This comes in very handy since I can insure that all of my mail is captured, organized via lots of labels, and I find that the Gmail Spam function catches a heck of a lot more spam and warns me of malware than most other packages. I can then send emails back as my other accounts. I also use Gmails labeling system to quickly organize a lot of my mail. I do not use them as folders as much as tags where I can place common terms that I use to quickly get to what I need. I also have the Google contacts in Gmail as my mine source for all my business and personal contacts so that it serves up my MobileMe, iPhone, Android, Outlook (ugh) and other contact applications. I love that functionality because all I have to do is make a single change which cascasdes throughout all of my applications and devices so I do not have to manage them all.

Google reader is the next major application I use. I make it habit for any website that I like to follow to use their RSS feed and place it into reader so that I can quickly scan for changes, select out what I want, and manage them. Google reader's new SendTo features are nice. Yet what really comes in handy is the ability to see other social network activity such as Twitter and FriendFeed in reader which greatly simplifies the overall timelines for people that I am interested in following.

Google Calendar is another application I use alot. I have it hooked into my calendar applications such as the iPhone, Android, laptops, and other operating platforms. The calendar does an excellent job of having maps for specific addresses in the Where location, I can share appointments, and from a management perspective, Google calendar lets me use only one interface that is essentially backed up on the cloud in addition to my other methods.
Google docs themselves are great. The ability to create forms, publish and share documents with others has been invaluable. However the extensions are even better. For example Google presentations can now go to SlideShare.net which is really convenient and powerful when I want to share out presentations. Also the Google document application which I normally use as Microsoft word also has excellent integration with Squarespace so that I can make my blog entries in Google and then publish them to my blog. This is tremendously helpful given the larger array of functions and presentation layouts that can be very beneficial.

These are the main applications that I use and they basically have saved me time, money, and make my life easier in managing a lot of different sources that best suites me.