Ever since I became a netizen about 16 years ago, email has remained the most important service of the Internet for me; this may also be the case with many other netizens. But having observed the behaviors of other people during these years, I have noticed two significant changes in the way many of them use email. The first change is that more and more people use web mail addresses as their primary or even only email addresses instead of those assigned by their respective providers, schools and/or workplaces. The second is that more and more people check email with a web mailer, i.e., through the online interface of the sites of their respective web or non-web mail services, instead of using a standalone mailer.
I myself use (two) Gmail addresses as my primary addresses for both private and professional purposes, forwarding to one of them those messages reaching the other addresses. It is true that the online interface of Gmail and other mail services has been improving constantly, but it has not surpassed the best standalone mailers in terms of functionality, customizability, hence efficiency. I need to spend at least twice as much time with a web mailer as with a standalone mailer because I have far less control over what I read and write with a web mailer than with a standalone mailer. The time I waste for each small operation may be tiny, but it can accumulate to a large amount of time because I, like many other netizens, use email all the time. So every time I receive an email message from a friend or colleague of mine who composed it with a web mailer, I cannot help feeling really sorry for the time he or she is wasting every day, perhaps even without being aware of this very fact.
I am especially sorry for those who used to use a standalone mailer, but once they have switched to Gmail or some other web mail service, they have also abandoned their standalone mailer, probably without knowing that switching to, e.g., Gmail, does not have to force them to stop using a standalone mailer. Actually, I think using Gmail with a standalone mailer is the most efficient combination with occasional use of its web interface, first and foremost in order to prevent my accounts from expiring (Gmail accounts will expire if you do not check them through the web interface for more than nine months), or while you are on the go without shlepping your computer.
I have been using a crossplatform open source standalone mailer called Thunderbird as my default mailer for nearly eight years since its version was still less than 1.0. In the first several years it was not so impressive, but as the time went by, it has become a quite sophisticated mailer. I have also tried a number of other mailers, but none of them has impressed me so much as Thunderbird in functionality and customizability. It allows you to add many functions through a variety of extensions.
An extension called BiDi Mail UI turns Thunderbird into one of the best and rare mailers with excellent support for RTL text direction as in Hebrew. But what I consider the most important for Thunderbird is a calendar extension called Lightning. Since I started using it a few years ago, Thunderbird has evolved from a communication tool to a personal information manager for me, i.e., I also use it as an electronic scheduler. I know that some of those who are otherwise computer-savvy still stick to paper schedulers, but they have to be aware that this way they are also wasting time; besides, paper schedulers cannot alert you about forthcoming events and tasks. Thunderbird also has some other built-in functions and other extensions which make it a very efficient personal information manager.
Many users of Gmail may also be using Google Calendar. In this respect I also prefer a standalone electronic calendar to an online one. Besides you can also check integrate Google Calendar into your Lightning through an extension called Provider for Google Calendar.
If you feel like trying a standalone mailer for the first time or after years of interval, I would strongly recommend Thunderbird to you. For people like you I have a webpage called Thunderbird: Guide for the Perplexed, which is the most popular page on my website TS-Cyberia. You can download the software for free from the above link to it. As is well known, there are two ways of checking email with a standalone mailer: IMAP and POP. You can check Gmail with Thunderbird in any of the two ways. But unless you are completely sure about your eventual switch to this mailer, please choose the former method. Gmail Help has a page explaining how to configure Thunderbird to check Gmail with IMAP. Even if you should decide not to switch to it in the end, you lose no data from your online inbox. Personally I prefer POP, though it is considered an older technology. But please do not try this method if you are not sure yet about your switch to Thunderbird, as your data will be transferred from your online inbox to that of this mailer. Again, Gmail Help has a page explaining how to configure Thunderbird to check Gmail with POP; I have been using this method together with the so-called recent mode. If you do not want to install the program on your hard disk and you use Windows, you can also try Thunderbird Portable, which you can install on your USB flash memory.
* Warning: It is true that Microsoft Outlook has similar functionality, but it is less customizable and is bloatware.
* Disclaimer: I have no commercial interest with this noncommercial software.