Trademarks are fairly clear cut. A trademark needs to be registered and it
generally takes the form of something that isn't an existing word or phrase. It's easy to find out if someone has registered a particular trademark and not generally a big deal if they have (typically this is just a branding issue).
There is legal recourse if the trademark enters the common lexicon (as happened to aspirin [1]).
Basically I have no problem with trademarks except when people decide to trademark what is the generally accepted phrase, as happened with the ugg boot [2], which has long since been a generic term in Australia.
Copyright is a little greyer but basically OK. It just needs to be protected from copyright trolls like Righthaven [3]. The danger here is that lots of low-quality or automatically generated text will be used as the basis of copyright violation lawsuits. Generally speaking, it's extremely difficult to independently come up with the same exact text as someone else for anything nontrivial in length.
The problem with patents is that two people can (and do) come up with the same idea completely independently and that many of those ideas are completely obvious (eg I remember seeing an early GPU trademark that related to applying 2 or more textures to a pixel in a cycle instead of 1).
I can write a computer program and it will quite possibly violate any number of patents. I can write a book and it almost certainly won't (randonmly) violate anyone else's copyright. If I want to trademark something it's easy enough to find out if it's already been trademarked and to trademark it myself.
Software patents are beyond moronic.
[1]: http://en.wikipedia.org/wiki/Aspirin#Trademark
[2]: http://en.wikipedia.org/wiki/Ugg_boots#Trademark_disputes
[3]: http://en.wikipedia.org/wiki/Righthaven