Bob,
Just because some sites may be doing bad things does not mean it's a good idea to replicate their methods. Not only is Google getting more aggressive and finding such tactics more, unless a comprehensive audit is performed on any single site, it's a blind guess as to why any particular site is truly ranking for a given phrase. They could be doing five crappy things and yet they could be ranking because of five other things they're doing right or better.
Or they could be ranking due to the crappy tactics, yet could just as easily crash next week or next month if they're just "getting away with it" for now.
It's great to hear you've had your penalty lifted, yet that also fits with the notion that you now have to earn your rankings based on more sound, long term methods. Anyone who just wants to find new ways to cheat the system is setting themselves up for a bigger fall down the road.