Can change screen capture format from png to jpg, pdf, etc.

Using it (previous version) on 10.4 and I tell you, this app rocks! Excellent mainly for laptops (not usually to have it on 24h/7d). Runs the maintenance scripts when you want them to run, make some UNIX features visible (no Terminal needed) but is better to repair permissions with your Disk Utility (not a law).
Unfortunately no more upgrades for Tiger.

This is typical 'bling'. Switchers who have bought RAM Optimizer Pro and stuff on Windws (or even used XP-Antyspy and stuff) will love this, but, I'm not complaining: after all there is added value as some of its functions are sometimes even, if rarely, of real use and you get it for free. Yo. But why does it need an installer, again? If you prefer it less esoteric 'applejack' is the way to go. Also, log files are there for a reason!

OnyX is a great utility for all OS X users to have.

Excellent program. Downloaded this in a desperate last bid to get my mac in shape after frequent spinning beachballs and crashes.

Since installing and running a few scripts/cleanups I haven't had a single problem. Highly recommended!

for Tiger. Version 1.9.5 for Leopard is available.

Without question the best and easiest way to keep your mac in shape.

The best system maintenance/optimization/customization app I have ever used. Hands down. + It's free, unlike other apps like it. I have never tried Applejack though, but I don't really need that kind of power.

Addenda to my previous post:
The installer has returned in the latest nightly build of OnyX 1.9.0 for Leopard, released just today. (No more drag & drop to install.)

I don't know what beta version Cayayofm is talking about, but yesterday I noticed a strange behaviour of OnyX 1.9.0 (lhe latest nightly build).
I launched OnyX and just took a look at the features. I did not run any routine, so I suppose it did not perform any action. (And I did not click any button by mistake.) Then I quit OnyX.
When I activated the Dashboard, all widgets were starting again, just like they do the first time you launch the Dashboard after a boot. (I don't remeber this beahviour when I had Tiger installed.)
I have already emailed the developer about this and I'm waiting for a reply.
Just one more note: The installation of this new version for Leopard is now done by drag & drop. No more installer to run.