My Artists ($1.99) by Top Drawer Apps is the perfect companion app to go with the iPod.app on your iPhone and iPod Touch.
When you first open the app, it'll display all the artists that you have on your device, and pull images to go with each one from Last.fm. Hey, it sure is nice to see a picture of the band that you may be listening to in the next few seconds.
Find an artist you want to listen to? Select it, and you'll get a bigger photo of the band and even a little bio section that you can tap on to view fully. Below that you'll see the albums that you have on your device, but that's not all. Underneath the albums that you have, you'll find even more albums by the same artist, so you can see what you're missing (at least on the device) at a glance.
Tapping on one of your albums will bring up the track listing, of which you can tap any song to start up the iPod. You can also get a full bio on the album itself, which is pretty awesome. If you tap on an album that's not on the device, you'll get a listing of the tracks with YouTube links, so you can watch/listen to that as a sample.
When you're playing one of your tracks, you'll get a super slick looking screen that will show a photo of your band and display the album and track that's currently playing. There's a volume slider, pause button and previous and next track buttons that will control the iPod app. Tapping the photo of your band will bring up the bio section that I mentioned earlier.
You may notice the "Explore" button at the top right corner of the Now Playing screen. This will bring up band bio, YouTube videos, and the best part - Discover.
Discover will bring up similar artists to the one you're listening to, and show the genre(s) too. Tap another artist to see what popular albums they have (as well as more albums). If you choose to select a genre, it will pull up some artists that fall into the same genre, which will then take you to the same kind of screen I just mentioned.
If you exit out of the app, it will resume the same state you last left it in thanks to iOS 4. Since the app plays your iPod, you'll find the iPod controls in the multitasking tray (when you slide it to the left).
I think this is just a great companion app to go with the default iPod app. It's a gorgeous interface that is already optimized for the iPhone 4 Retina display. Everything is responsive and beautiful, and I've experienced no crashes. It's just a very polished 1.0 app and it's clear that the developers spent a lot of time into coming up with the design and layout.
If there is one thing I have a problem with, it's that there is no button to go back to the main screen where all your artists are listed. You have to tap through all the screens you've viewed just to get back to that artist listing. It would be nice to see a button that will take you back to that screen automatically.
If you use the iPod app on your iDevice frequently, then this app is definitely a perfect match to go with it. Or heck, even replace the default iPod app with this! Get it while it's on introductory sale pricing before it's too late!