re: Proper Etiquette - Current Company Trying to Retain Me

Lots of good advice here that's already been stated and here's some of mine:

1. You signed the offer. Be a man of your word.
2. Why did your current company take so long to counter offer? There's reasoning there. You might want to consider that.
3. If you stayed at your current company, what would future raises look like? I bet they'd hold that big raise over your head for many years. Worst: They may make you sign an agreement not leave for XX years and trapping you.
4. One great piece of advice that was stated: What's the future of both companies? Who do you have a future with?
5. New company...new baseline for salary. You're probably maxed in your payband for your current position with your current employer. Your raises are probably already getting compressed to essentially nothing.

Definitely take the new job.