I think we all get drawn to certain artists for different reasons... If I pull a nice sketch, even if it's not a valuable one, I'm often driven to find others by that artist. Ashleigh Popplewell was one of the first decent sketches I pulled and since I've collected a number of hers and just bought some AP's she was selling cheap on ebay, so looking forward to seeing them when they arrive.
I was going to list my favorite artists, but the list was way too long ! And there's nothing that says that valuable cards are more enjoyable. I've been haunted in my breaks by Mauro Fodra, his art is nice, but doesn't gather much attention or value...but I'm seeing improvement in each release, so much so I actually bought one of his off ebay for my character PC...a total steal for $17 US !!
I also appreciate it when the artist goes to the effort of making the card the best that they can do, no matter how evolved their skills. On any day you can give me a $25 full colour sketch with background by a nobody over a pencil sketch by a bigger name that might draw 4 times as much value.
Not sure how others think, would be interested to hear, but I work on the principle that the average sketch from a $60-80 box has a value of about $30 or so. Looking through my breaks and there's probably only a couple that I think are blatantly worth less than that, and the majority would be slightly more with only a few real standouts. The high value cards are rare, but I've been lucky to pull a couple. Product also plays a role, Star Wars stuff for example has been pretty bad to me, with only one sketch of three breaks really being up to par.
Anyway, in the end, it's up to you and what you like. Watch other peoples breaks, scan the forums and you'll start to build up a like for certain artists I'm sure.
Oh and nothing beats the thrill of the chase to find that really nice piece, but then again, I think I'm pretty much box break crazy these days...LOL! Stay tuned all, big breakage coming tomorrow !!