Perhaps ease of culture in your conditions in zone 7 may be a major factor.
Two easy to grow species here are Cattleya intermedia and Cattleya maxima. Zone 7?

Posted pics of some varieties of Cattleya intermedia over on the photo gallery.

While it is neither pink nor white, the easiest Cattleya species IMO is Cattleya forbesii.

Please, note that I am in Md, not far from Pa, USDA zone 7 (barely), latitude 39N.

--Stitz--

My favorite is C. (Laelia) purpurata and I am trying to collect all variations. This is a species I don't mind having duplicates sitting around taking up space.

This is the purpurata v. werkhauseri {{gwi:151013}} This is purpurata v. flamea {{gwi:151015}} This is purpurata v. carnea {{gwi:200492}} This is purpurata v. aneleta {{gwi:200493}}

I'm now trying to collect as many C. intermedia {{gwi:200494}} Intermedia are smaller growers if space is an issue and there is a very wide variety available.

Enjoy the pursuit!

Brooke

I love intermedia for the ease of growing. I have collected quite a few vars
I love Catt bowringiana - it is strikingly beautiful when covered with blooms. I especially like the coerulea vars. Easy to grow.
Like Brooke, I collect Purpurata - my favorite. Lots of vars out there to keep a collector happy. Mine bloom with lots of light.