Advice on speakers for a vintage system

Help. I recently took the plunge and had my father's old McIntosh setup completely refurbished (thank you, Circle Stereo). It's a pair of mono blocks, MC-30s (30 watts continuous output), and an MX-110 preamp. Now, I need speakers to run them through. I'm an audiophile newbie and don't know much about power demands, crossovers, etc., so I'm asking you experts for recommendations about minimum specs and possibly brands of speakers. Can any of you take pity on a novice and give some advice that a neophyte could follow?
I would stick with vintage speakers. Plenty of JBL, Altec, and Klipsch speakers available on ebay. These companies rarely bad speakers in the past and many of their designs still beat many modern ones. Which you pick depends on your budget and room size and shape. Enjoy!
This is a killer little system you have, and you should count yourself very lucky indeed. I would personally avoid vintage speakers unless you know they have been thoroughly checked out. If you go new or used, just make sure they are tube friendly. I would suggest 6 or 8-ohm speakers, as these tend to be easier loads than 4-ohmers. Because there are so many types of speakers out there, I would keep your selection criteria very simple (your listening space and how much you are willing to spend). Then, find a reputable dealer, give him your criteria, and sit down and listen on a Saturday afternoon with YOUR CDs. Whatever you do, do not buy blind! Also, make sure you take some time to learn how to maintain your new gear (i.e. changing tubes, never powering on tube amps without speakers attached, turn on sequence, etc.). Once you find some speakers, you will have one sweet little system.
I wouldn't monkey with true vintage speakers (70s era)unless there is a specific model that intrigues you...however going used does reap some benefits...some suggestions: b&w matrix series, Boston acoustic VR series, Psb stratus series, Paradigm studio, etc...many options out there
Klipsch speakers is the way to go, vintage models only if you want to hear what the 30's can do. Enjoy the music, he would be proud.
...also if you can find Electrovoice....they are good as well
second klipsch - classic series - like the Heresy
I use my Dynaco MK3s with AR-90s. I listen to alot of classical music and rock and roll.
Thanks to you all. This has been very helpful. I'm really looking forward to seeing what comes out of these babies.