In terms of SEO, descriptive URLs for inside pages are best. Try to avoid abbreviations or shortening/combining words until they’re nonsensical jargon. Easy enough to remember. But, on the flip-side, there’s speculation that being too descriptive (and too long) and come off as spammy, and may actually hurt your search engine ranking.
So, what’s too long? Here’s an example discussed on Seroundtable.com:
http://www.gadgetguy.com.au/small-kitchen-appliances-toaster-kettle-coffee-machine-blender-juicer-channel7-sunrise-australia-42.html
Wow, that’s a lot of keywords crammed into one URL. Even if it’s not clear if such a long URL would hurt a page ranking, you can be almost certain no one would remember that URL, which is another reason to have concise ones to begin with.