I've already used many emai services and messenger as well...
Initially I used to use ICQ however MSN came with betters options and sudenly everyone here in Brazil, started to use it and ICQ has been forgotten since that time O.o...
I'm still using MSN and no other... Have already tried Yahoo! Messenger, Trillian... Jab...
About e-mail... In the past I used to use many many e-mails however it started to bother me and then when gmail arrived I got a invitation fast and I've using it for a long long time now... I don't intend to change it never more...
One webmail that I really enjoyed it www.fastmail.fm as it has some options that is hard to find for free...

Hmmm i use msn, gmail and i host my own e-mail server to, to host is good fun but can be a pain if your net connection goes down as i need a constant connection to the internet and sometimes i dont get it

I'm using the hotmail system, with our new pc it was quite hard, because windows xp made it possible for several accounts on 1 pc, but each user used outlook express, and the mails were stored in the account that was loged on, so mails got lost etc, (now i know you can have more mailing accounts)
it took some time to change all my internet accounts on my new email adress, but now the problem's are solved,

i also used AIM messenger, but I forgot if it had a mailing system too.

Mostly everone I know (actually everyone) uses AIM (AOL Instant Messenger. Yahoo! Messenger isn't popular at all around here and most of my friends would be lucky to have ever heard of MSN Messenger. I use SBC Yahoo! Mail (AT&T now) because that's my ISP, but its basically just Yahoo! Mail.

I go with yahoo. I think the inbox is a good size and I can access it from anywhere. I ahve about 2 names and that is what I like about yahoo. You can sign up for mutiple names.

I am using Hotmail, because i am using msn messenger. That was a BIG stupid misstake i did. I got so much junk mails on my hotmail adress, that it would be better to have my hotmailadress just for msn, and another email for my mails.

/Krille

I started with an MSN account back when I didn't know of the existence of Yahoo! Messenger. I used it for IM's but I mostly recieved my emails on Excite.

When I discovered Yahoo! Messenger, I switched to it, especially when I needed it, back then, when Yahoo! groups were (and probably still are) the most common way to do something as a group (share pics and files, mail, collaborate, etc)

I got myself a Google account when all the hype came up, although I never fully appreciated it.

I'm sticking with Yahoo! especially now that it can send and recieve IM's from MSN. The only objectionable part, probably, is the buzz button. Sure, it's really useful for getting your partner's attention when you have a question that really needs answering. In the hands of noobs and unethical mannerless idiots, however, it can be grating on your nerves.

Oh, yeah, audibles too.

Personally, i have use Yahoo messenger and Gtalk - The Google messenger. Out of these two , i would vote for Yahoo messenger. Here is what i make of these two ..

Yahoo:

First of all, i would simply love yahoo messenger for its plethora of services... You can send/recieve files, chat , voice chat, video confernece , audio conference with Yahoo messenger.. Recently ,they have also introduced plugins to add new features to your messenger. You can access terrific services like Yahoo Launchcast Radio, Yahoo Answers , and Yahoo 360 ..

Let me tell you two main reasons i use Yahoo messenger..

1)It has a stealth mode option, which allows you to choose,who all you want to be invisible to, and who all you need to be visible.. To be more clear,.. you can appear to be online to some people , say your friends, and be in invisible mode to other people ,say your Boss..

2) Confereces... These conferences make life lot easier to me.. Instead of just arguing the same thing with my different friends in different chat sessions, it is so simple for me to put all of them together in a conference session and discuss any issues..

GTalk:

To start with GTalk, it is a 'neat' and 'Light' messenger.. It does not have a wide range of options like Yahoo.. But it does offer the best of what it does .. You can voice chat in Gtalk too,, But no conferences and no stealth modes. These are my main concerns about GTalk.. I also have to mention that GTalk's file transfer scheme does not seem to be as good as Yahoo messenger's (Atleast in my case). All your chat history gets automatically saved in your Gmail . So thats something useful to have. And one big advantage of GTalk for me is ,it is the only messenger that my school does not block !!!!

Trillian

Apart from these two, i have also tried Trillian. It is a messenger that allows you to access Yahoo ,MSN,AIM etc.. So ,you can call it a 4 in 1 messenger.. You can also log in to multiple accounts of the same provider at any given point of time.. Ideal for people who have many IM accounts to deal with..

In my opinion Yahoo, would be the best messenger ... GTalk needs some more features to go with it before it competes with Yahoo . I have not used MSN messenger yet.. I'll give it a try..

I use MSN, simply because it's fast, completely free (yaaay!), and has a massive network, with more people connected to it than anyone else. It offers alot of support, and an easy to use interface. Mostly though, it is because you can simply get into contact with so many more people than any other servers, and because all of my friends and contacts use MSN.