I have a couple of plugins I use with Lightroom 4. One is Topaz BW Effects the other is Nik's Silver Effex Pro 2. I bought them all 'on sale' so price wise they were a decent deal.
I don't often use them so I thought I would give them a try today on a shot I felt color had no real benefit.
click on image twice for larger view
This one is from Nik's - Silver Effex Pro 2 (Full Spectrum I think)
This is from Topaz BW Effects (one of the infra-red settings)
What I like about the infra-red is , it makes the sea gull waste appear to look like paint flakes or gum much more attractive
I think these plugins have their usage - They are both pretty powerful and offer complete customization from the presets.