Ask yourself this simple question... when going for that interview against many other similarly situated candidates, what's going to make you more interesting to the interviewer... that you actually attained some practial experience doing legal work or that you took a few classes while enjoying a european vacation?
While that sounds a little harsh, just remember how rough the job market is right now. Any plus you can get over other candidates is something that will make you more interesting to the firm, so what gives you that plus? I'd say it's the 'real legal experience' as opposed to the 'academic opportunity'.
Of course, in theory the reason people go to school is to obtain an education, so if your first focus is on being a well-developed student, then go with the study abroad.