[euphras]

I still use a 867 MHz Powerbook with Tiger 10.4.11 as my daily workhorse. It´s just fine for graphics, writing and other things. But the web-experience is getting worse and worser. Sometimes it takes minutes to load a page, and more and more pages do not load at all. So i´m looking for a new used one in the bay. I want a machine running Rosetta, since i simply want to transfer my hdd with all the programs and data to the new book. I don´t want to spend money for Adobe PS, since under Rosetta the old programs run with a decent speed regarding my needs.

Is there a specific model family i should look for? Maximum processor power and the ability to run Rosetta?

[reader50]

Mac Book Pros that can run Snow Leopard (the last OSX with Rosetta). Earlier models will too, but they can't run the latest OS (Sierra) so they top out at El Cap or earlier. Eventually will be isolated since El Cap can't read APFS disks.

2008 (early or mid) can run Sierra, but the wireless does not work.
2008 (late) or 2009 is the minimum if you want to run Sierra too (or someday) without glitches. Officially unsupported, but Sierra runs fine. Core 2 Duo CPUs.

2010 jumps to Core i5/i7 CPUs. Sierra officially supported (no workarounds needed to install). Max CPU: 2.8 GHz 2-core.
2011 (early) adds quad-core CPUs. Max CPU: 2.3 GHz 4-core.
2011 (late) came with 10.7 Lion as minimum OS (no Rosetta), though unofficially it boots into Snow Leopard. Max CPU: 2.5 GHz 4-core.

2012 and later: not Snow Leopard compatible. Unless you want to hackintosh it, with kernel substitution, hunting around for assorted drivers, etc.

If your MBP came with 10.7 or later on it, you might need to install SL from a different Mac over FW or TB. Apparently the presence of a recovery partition confuses the SL installer (i haven't tested this). Possible workaround: use Disk Utility to delete recovery partition(s), then boot from the SL disc. After install, SL has no trouble with recovery partitions being present.

[OreoCookie]

What you are asking is nigh impossible and at the very least not advisable as a long-term solution. Rosetta was last included in 10.6, so you'd continue to rely on an OS that is no longer actively supported and you are stuck with very old machines. Hence, you won't be able to run any modern browser (Chrome requires 10.9 or later, Safari also requires newer machines).

Let me propose an alternative solution: there are plenty of quality Photoshop-like editors out there, Pixelmator and Affinity Photo are two from the top of my head. These are not Corel Draws or Photoshop Express replacements, Affinity Photo has won Apple's Best Mac App of 2015 Award and Pixelmator also has won an Apple Design Award. Since you haven't felt the need to upgrade from Photoshop CS or so, I reckon these will fill your needs just fine. Serif also makes Affinity Designer. Affinity's apps cost around 50 € each while Pixelmator is even cheaper (~25 €). There are also plenty of very good vector graphics applications out there for similar prices.

If you want to have a machine you can rely on for a long time, it makes no sense to get one that has already 10 years under its belt and isn't supported any longer. Do yourself a favor and get a brand new machine, or one which is as new as possible. The used market right now is great, because even ~3 year old machines aren't that much slower than current ones (which is Apple's fault).

[Doc HM]

I'd go with a 2011 quad i7 macbook pro as it's still a competent machine and you get thunderbolt connectivity.

I would NOT just sling your old HDD in there, but rather partition the drive (which will be waaaay bigger than your old drive anyway) and clone your Snow Lep system etc onto one partition and then install El Cap or Sierra onto the other. That way you can always boot into a modern OS since many websites/browsers now fall over in SL.

Best of both worlds. 2011 15in i7's are also pretty bargainacious!

[Waragainstsleep]

Bear in mind if you get any Intel based Mac you aren't going to be able to just transplant your current drive. You'll need to migrate instead. The 10.4 build running on a PowerBook will be PPC instead of x86.

[Doc HM]

Originally Posted by Waragainstsleep 

Bear in mind if you get any Intel based Mac you aren't going to be able to just transplant your current drive. You'll need to migrate instead. The 10.4 build running on a PowerBook will be PPC instead of x86.

D'oh! Missed that!!
PPC era seems to have slipped from my mind!