not so many, maybe 20 (i count as example the alien box or planet earth box as only one). i bought hundreds of dvd's when i was younger and when there was no blu-ray on the market but then i realized that i don't watch most of them more than one or two times so i stopped purchasing movies like an addicted. rental is enough for a movie i only watch one time... nowadays i only buy them rarely when i really really like the movie or if it's a nature docu because i watch these plenty of times (or parts of them)