Well doing that kind of thing wasn't exactly what rickh was recommending. He simply was suggesting the opinion of many
Debian users that building the
NVidia driver and module will be more customized for the
Debian system when done using packages built with that in mind rather than the one size fits all
NVidia script.
Each package you pull from Sid with the -t unstable switch brings in that package plus any additional dependencies and recommends that can't be satisfied with available
Lenny packages.
So, the more you install from Sid, the more you are running a mixed Lenny/Sid system. The packages not released into testing are delayed for a variety of reasons, but unless the only reason you see on the developer page for "Why is this package not in testing yet" is that is can't be built on other architectures but on yours (normally i386) it's okay, then it really isn't ready, as judged by bugs, time tested, installable without breaking some other
Lenny package, etc.
For example, if you look at Icedove you'll see things like new bugs introduced by the upgrade, upgrading some things needed as dependencies makes a bunch of other
Lenny packages uninstallable, etc. Until these issues are sorted and fixed, the newer Icedove is not ready for
Lenny.
I'm not saying it will positively break things that you use or will notice if they are broken. Many times pulling in specific packages works out okay. But it is counter to the
Debian way of ensuring stability by way of sticking with one distribution and using
Debian packages whenever possible, which was the whole point of Rickh's advice regarding doing the
NVidia installation the
Debian way.
Most often, if what's in testing doesn't satisfy then the best approach would be an upgrade to unstable. A full unstable system with a more careful approach regarding software upgrades is likely more stable than a
Lenny system mixed together with a bunch of Sid packages. That is the approach taken by the Sidux distribution. The same approach is used by many users of Sid proper (not going with the Sidux fork).
I any case, this stuff makes for an interesting discussion!
I just wanted to stop you in your tracks with the reminder, if you didn't realize it, that you are NOT safe from changing your system to Sid just by making the default release testing, if you personally -t unstable a bunch of Sid packages. You can be bitten by some of the dependencies pulling in packages that are not yet in
Lenny for good reasons.
No problem with a single proprietary driver binary install, perhaps, but it is not a good idea to go forward pulling software in as you suggest. But since it is your system, enjoy.
Personally, I've always used the
NVidia downloaded script on any distro and enjoy the latest releases, betas with their fixes, and support from
NVidia tech's when doing that. I only added Sid at one time to get that 2.6.22 Kernel in the days when we needed it for
NVidia. I still used the script. But, to each his own.