Oh dear, that's not good Dup .... that's kind of the position I was in around 5-6 years ago when a friend lent me a copy of Spirited Away ... it was all downhill from there ... make sure you have plenty of space and start saving
Regarding the Ghibli list above; be aware that Only Yesterday and Ocean Waves are slice of life films as opposed to the fantasy of most of the Ghibli films, (I like Ocean Waves but find Only Yesterday a bit meh). Grave of the Fireflies is very depressing and can be quite hard to watch whilst My Neighbours the Yamadas is just plain weird at times.
Other things it is worth looking at:
The Girl Who Leapt Through Time is an excellent film.
Code Geass (original and R2)
Eureka Seven (the series is a lot better than the film (and now available in two £15 parts))
Full Metal Panic (first and third series are a mixture of action and comedy, the second series Fumoffu is comedy)
Samurai 7
Samurai Champaloo
Burst Angel
edit:
Should also add:
Steamboy ... along the same vein as Ghibli
The Little Norse Prince ... a kind of pre-Ghibli directed by Isao Takahata with Miyazaki as one of the animators
The Castle of Cagliostro ... a Lupin III caper film co-written and directed by Miyazaki (also pre-Ghibli)
I'll also add the general reminder (not just aimed at Dup) that the "complete collections" of Ghibli films on auction sites are bootlegs rather than genuine releases.