Shorter or even purposed-use (e.g. mybrand+TV.com) vanity domain names work well for TV or radio DR... especially if the domain types-out like it sounds - I'd suggest not resorting to hyphens/dashes, and of course one-word is only useful if it's not a probable in the final rounds of the National Spelling Bee; without "misspellings variation" PPC to support it, a domain like that of Orbitz or would be a bad on radio.
Repeat clients or those responding to a branding effort may also do better with a vanity name, same goes if you are a keynote speaker or handing out flyers or (verbally) naming yourself at a trade show. Basically, if a client has to type it in, it will naturally get reduced by a fair minority.
So go for it if after that, it makes sense - what's $35/yr? But it is very easy, especially for smaller companies, to dilute themselves quickly. Thus 301 redirecting works, but while you haven't posted the two ideas, be sure to carefully consider your brand, proposed "vanity" domain name, and think from the perspective of a consumer hitting a SERP result... if what you are considering as a primary landing page domain name looks long and spammy to you... it will to your clients.
All just my opinion of course.
