I was classically trained, and used to be a performing classical guitarist. I have since "merged" those techniques with techniques that I picked up from other styles -- folk, blues, jazz, rock and roll, etc. Like some of the folks who posted before me, I don't see any inherent conflict in this. In fact, there are a lot of folk musicians out there (past and present) whose approach incorporates many elements of classical performance -- including musicians who spring from Celtic, African, Appalachian, and blues traditions. I think that an awareness of a range of traditions, and an ability to recognize the things they have in common, can only make one a better musician.

I also have to agree with Benjamin about improvising in classical music. In fact, improvisation was an integral part of musical performance in the Baroque and Classical periods ("classical" is currently used as a generic term, but it also refers to a specific musical genre and time period in which Mozart, Haydn, and others were composing). A number of people who heard Beethoven perform remarked that his improvisations (which were featured on the program) surpassed his written works, which boggles the mind when you stop and think about it. Classical improvisation fell out of fashion in more recent times (most of the 19th and 20th centuries), which is unfortunate, but it is nice to see some musicians bringing it back. I think that for a while classical music pedagogy did stifle a lot of the creativity that people wanted to bring to the music, and possibly drove a number of them to give up their studies and pursue more folk-centered forms which offered more creative freedom. Let's hope that we "folk" musicians (however one defines that term) can avoid making the same mistake.