Heh, heh -- congratulatons, you are hooked!
From this and your other post, I am guessing that what makes the Addis work for you are (a) the very flexible cord and (b) the fairly blunt points, which slip into the stitches without splitting the yarn (especially "difficult" yarn like boucle).
If you start doing precision knitting like lace or socks, you may find you want sharper needles. The KnitPicks needles are sharper than regular Addis but Addi also makes gorgeous lace needles with thin cords and tapered, pointy points. Hiya Hiya also makes excellent sharp-pointed needles at a very good price.
The thing about collecting good needles is, you don't have to go out and spend a pile of money at one time. Buy the size you need when you need it and in a couple of years you'll have a collection of tools that are a pleasure to use for a lifetime.
BTW: There are several dealers selling Addis on Ebay at big discounts. The needles often come in German packaging (Addis are made in Germany). If you go that route, and are worried that the needles may not be authentic, be sure the seller has close to 100% positive feedback. I've bought many needles that way and have always been pleased. Just saying.