I know this is an old topic, but let's approach it in a new way.

Rank the options in order of effectiveness
put a divider in to the list below which you think gaming is not effective
Put an asterisk by ones you have personally tried

For instance:

Skype/Google Hangout*
Fantasy Grounds (or Screen Monkey or other online gametable software)
Play by Post*
>----------<
Play by Chat
Play by Email

Once a number of people have posted, maybe we can discuss.

My list:

Play by Chat*
Skype/Google Hangout*
Fantasy Grounds (or Screen Monkey or other online gametable software)
>----------<
Play by Post*
Play by Email

I have one IRC game which just finished its ninth year, and another entering it's fifth year.
Skype works fine, though I have nowhere near the experience I have with IRC.
I have not tried any gametable software - I have never needed it, as I do not use games requiring precise positioning - but have no doubt it works well for those who use it.
No Play by Post game I have ever been in has achieved a satisfactory conclusion. They just seem to dissolve ineffectually.
Play by Email would seem to be a slower, more cumbersome version of Play by Post.

-clash

For me its:

Fantasy Grounds and Skype/Ventrillo

My Backups are:

Maptools and Skype/Ventrillo (though problems with connecting to the server can be tricky)

Infrno with Skype/Ventrillo

Skype plus Epic Table/Map Tools* (was Fantasy Grounds (or other online gametable software))
Skype plus Catch Your Hare Die Roller*
Google Hangout*
Play by Post*
>----------<
Play by Chat*
Play by Email *

Can't you follow directions?

Tell me more about Ventrillo. I guess I don't know that one.

My real (not example) list would be:

Skype/Google+ Hangout* (Intrigued by tabletopforge.com. Been testing it and it looks great!)
Play by Chat*
>---Play by Post*---< (On the verge of not acceptable play - depends a LOT on system, # of players)
Fantasy Grounds* (just TOO much)
Play by Email
Play by Txt (Funny idea. Wish someone would make a game for it.)

I kept a Play-by-Post Marvel (MSHAG) with home-made heroes going for 2.5 years and it was pretty good.

I can, but I march to my own drum and don't just follow everyone else blindly.



It's a free software to connect to Ventrillo servers (the software is available for free as well).

The site can be found here: http://www.ventrilo.com/

It's nice because the server can be set up with different rooms and you can do push to talk so people aren't talking over eachother.

I have a vent server and I use it for my games and the players prefer it because the sound quality is better. Unlike Skype (which is good, I use it) where you are sharing servers with millions of users, with Ventrillo you are sharing the server with only the people connected to the server, causing less server problems.

And if you have a good high speed internet connection (which I do) it's great

Your IRC experience amazes me, Clash.
As for gametable software, I've enjoyed using it not for maps, but for representing physical elements (like pushing chips around for fanmail in Primetime Adventures RPG, to share pictures of NPCs and in world artifacts or to have rules cheatsheets).
I agree on PBP often fizzling out, but I actually ran a LAdy Blackbird game for about six months and finished it recently, it was awesome. I'm also enjoying ongoing games of Smallville, Burning Wheel, Apocalypse World, Star Wars (using Lady Blackbird) and there is a game of Remember Tomorrow starting up, too. I play for the moments of awesome, like watching snippets of great TV late at night that you just happen to flip to and didn't expect.
PBEM has never worked for me.

Yeah - I seem to have been singularly unfortunate in the PbP area. Other people I know seem to sometimes join viable groups.

My Sunday IRC game has been playing StarCluster since 1E, in 2003. It has been extraordinarily successful.

I could imagine using gametable software for my various dogfighting/flying games, in which beads or tokens are moved around on a Vehicle Control Sheet from state/box to state/box. That would make a lot of sense.

-clash