I am in the process of re-building my Lightroom Library after attending a workshop on LR 4
While I agree for long-term preservation and conseversation, DNG is a good solution, however if you are using Lightroom you need to consider what it is you actually want (vs. what you think you want) out of DNG.
Yes, DNG is a good long-term solution, but short term, the odds are that current and new cameras will not lose support by ACR/LR in the foreseeable future. So, what will DNG give you in Lightroom? Well, a bigger backup actually. If you convert from raw to DNG, all settings are stored directly in the DNG file. What that means is if you "touch" that image by making any adjustments (or editing the metadata) the changes will be saved inside the xmp headers in the DNG file (assuming you actually save the xmp to the file). Conversly, if you use the original raw file, LR will treat those as read only files and save all the settings and metadata in a .xmp file which is a tiny text file. So, with DNG, a date modified will require a backup of the entire DNG file (multiple MBs) but if you use raws with sidecars, they are tiny text files (think 500 KBs).
DNG is a really good idea, but it may not be an optimal situation for LR at this time depending on how you work. Yes, if you needs to send raw files to other people, use DNG so you can lock the settings, snapshots and metadata in the DNG file. But if you are only working for yourself in LR, you need to ask yourself how you want to work. If you (as I do) tend to write (save) settings to raw files, your backups of DNG files will be much larger compared to the tiny .xmp text files...
That was a VERY helpful answer