Hey, aren't you being just a little bit hard on yourself? I also pledged "no apps in 2009" but I've broken that. I got a Capital One card with a $500 CL and an annual fee, also.
Live and learn but don't beat yourself up in the process.
Only you can make the decision as to when is enough and at least there is support and advice to lean on here.
You seem to be ready for a 'cooloing' period and as a regular visitor to this site as well as the others you are on I hope you do for a while.
Good luck if you decide to stop , app'ing has addictive qualities to it and that is a subject I'm well versed on.
There is more at stake here than the 300 CL.
Just my two cents, good luck again.
BB-MC is one of the ones i fired without a replacement in hand.
Limit stunk ($650), CS stunk, pitiful CLIs - and paying to be treated badly didn't sit right.
When you are craving an app think about what you HAVE (works for me, but then I still get a letdown when I check the mail and there isn't a new card). I ask myself: why the ___ do I need another card --- if maxed the ones I have now I would have to declare bankruptcy! If I REALLY NEED a 'new card' I'll change the design on one I already have.
Its done, you did it, and definitely move on. Learn from this and just don't do it again for awhile.
Also I would recommend that you cancel the card or call to have the AF waived. If not, then cancel it. You have a lot of cards already and you don't need to pay an AF for this card.
You took the hit for the inq and new TL, but that will go away.
Have your eyes set on something you want with a timeline and that will hopefully prevent you from applying again for awhile.