Meaning "Elite", which on the internet is spelled "31337". This was then shortened to "1337" or "l33t" and pronounced "Leet". A l33t is one who "pwns" (owns) "n00bs" (players who are bad at a particular game) all day long locked away in their dark room, perhaps hacking a mainframe or two. Closely associated with h4x0rz (hackers) that are good at what they do.

As the Internet was coming into its own, during the early 1980s, hackers that didn't want their websites, newsgroups, etc, to be picked up in a simple keyword search began using numbers to replace certain letters (mostly vowels) such as A = 4 or E = 3.

At this point, l33t speak was only known to a select few and only used when necessary. However, in 1994, id Software began to add Internet connectivity to Doom and Doom II, leading to a revolution in PC gaming and also to the rise of l33t speak.

As with any type of competition, 'smack' talk became prevalent in online gaming. Phrases such as 'I am elite' became common place, and somewhere down the line l33t speak crept in, reforming the phrase into '1 4m 3l1t3' in order to demonstrate that the speaker was a hacker and someone to be feared. It was further exaggerated by purposeful bad spelling and eventually wound up as something like this, '1 4m 3l33t!' and simplified to, '1 4m 133t'. Hence the name 'l33t speak'.

l33t speak was still relatively unknown to the Internet masses at this point. It had almost disappeared from gaming entirely. However, a very popular web comic called Megatokyo brought l33t speak into mainstream with its infamous speak l33t? comic. These days l33t speak is very well known to the hardcore Internet community (especially gamers).

As you've already seen, basic l33t is just replacing vowels with numbers:

A = 4
E = 3
I = 1
O = 0
However l33t is a very flexible 'language' and you can go f...

An extremely well hung, l33t h4x0r online player; unbeatable; the driver of an automobile, especially of a getaway car.

Someone that has l33t h4x0r properties.

See crew

A l33t crew. Simple as.

It's totally uncool to pretend being l33t. You're never l33t till someone of the scene says you are. That's the scene rulez!

WINvidia is a partial acronym similar to wintel detailing the optimal configuration for a home PC.

It stands for:

Windows
Intel
Nvidia
V
I
D
I
A

also one should not the WIN at the start of the name, this is not sarcastic but rather this configuration is VERY win.