I have been using the same drawing software for... oh my god... when did Photoshop 6 come out? I used it, then got PS 7 when it was out and I've been using PS 7 ever since. Looks like version 8 (CS) started in 2003. So I've been using PS 7 since probably 2001. Now, I haven't been drawing digitally that long. I was using it to color and clean up scans prior to 2008 when I started using a drawing tablet.
Currently I'm testing out Clip Studio Paint. I messed around with Krita and Gimp and a few others but never "used them" to any real degree. But Clip is nice. So far I'm kind of loving it.