That was a smart move, especially if your skill-set was unique in your company. I've given this advice more times than I can think and I've been ignored at least half of the time. I can think of only one case where it worked out well, but that friend was a CEO at a multi-national and the board of directors was the salary decider. The others were gone within a year.

Be very suspicious if it's a huge increase in salary (or dwarfs your current offer), but generally any "counter offer" is not a good idea to take.

When you get a large counter offer, you have to think one thing: Why?

At first you may be inclined to think "It took me having a foot out the door before they finally valued me!" Unfortunately, what they've valued is the risk you represent. Within a few days, after your manager has discussed "contingency plans" for all of the things you did. You'll be spending the next few months making "the documentation a little more clear" and "cross-training" your colleagues. They may finally fill that position they've been promising to hire for to "give you some help". A few months of this will go on and someone in management will ask how your salary is justified (this will likely not be asked directly to you). Unfortunately, all you've been doing is documenting and training others, the real work that contributes to the bottom line has been ignored and you're now behind! How can they justify paying you so much if you're getting nothing done![1]

I even had a colleague who thought the answer was to turn down the job, take the increase and find another. It might have worked were it not for 2008. He went 6 months unemployed and took a job for a lot less than he was making prior to the increase (specifics were not offered or asked).

[1] It doesn't always (hopefully not even often) happen with such calculation or disregard, but a variation of this almost always plays out.