Well I bought a new Athlon XP2000+ with 80Gb HD, 256 DDR Ram, integrated Dolby sound, Geforce 2 gfx, LAN and 16spd DVD for the grand total of 400 UKP. One second hand A4000 with tiny HD, little Ram and 25Mhz processor costs more than that alone. Add a Toaster for twice as much again. Add more Ram (72 pin Simms at quadruple the price of a Dimm), one or two HDD's (bearing in mind the 4GB limits of AmigaOS and assuming you have somewhere to physically fit them), drop in a CG3D or Picasso and you have something to work with. Oh and don't forget you need to convert that crappy NTSC format in to a slightly more decent PAL format... add a converter or two.
Oh how these things mount up. Now I think my old Amiga is great, but which route would I want to go down if I wanted digital video?