I'd say the Radeon 9000 is better. Unlike the GF4 MX series, the Radeon 9000 series is DX8 compliant (full support for vertex shaders) and it has ATI's reduced rendering technology (if you can't see it, it won't be rendered).
You may also consider a GF3 Ti 200 with TV-out as they are comparable to a Radeon 9000, probably a bit more powerful but also more expensive. Bulk Radeon 9000's with TV-out are around $70-80, while most GF3 Ti 200's are around $90.
As to why some video cards have HSF units while others only have a heatsink - the ones with just heatsinks are lower-end cards (and thus they are cooler). For the more powerful and hotter cards, fans are also required. Don't be fooled by the "same specification" thing, there really is a difference if you look closely enough. If not, then some manufacturer took the extra time to put on a fan, too, so thank them very much!