Very nice question raised. We also invest in both and have been for a long time. I think we made much better deals with liquids over the years. The only thing is, when we started back in 1999, there was already barely any common English words available. IN fact, I wrote a program in January of 2000, which ran against common word and whois program and it returned a very few "desirable" results. To this day I own a few names from this program: Artistical.com, Biannual.com, Faite.com, Phenology.com, Utilizing.com. My point was not to advertise my names here. My point was that even back in the beginning of 2000 when I registered these, - and btw - I registered every single one word dictionary that was available at that time - even back then the available lists were not even that great. I got a few offers over the years and a few sales of course, but the quality was not there even back then.
My point is - in order to work with common English dictionary words - you need to go back to 1996 - 1997 and if you find a way - please share
As far as liquids - well you can pick one up today on the free market. It may not be that liquid today, but it's going to start melting soon and once more domainers come into the mix - it would be qualified as a liquid and potentially sold.
I feel like extreme number of extensions definitely hurt our bottom line with both liquids and common words, but it does give the new entry point to novices, and more domains to practice the trade.
Now, if you are a multimillionaire - then it's best to be common word trader - or some extreme liquid NN and NNN and LL, LLL up on the top of the food chain.
But best parts about liquids, they allowing everyone in. Just purchase today 8N.com on the open market and hope for the best.