appshopper, it has a "my apps", to keep track of what you already own. "wish list" just add what apps you want, and if they drop in price, the app will send you an email and a push notification!.
Then there's the "what's new" that is always up to date, and you can set it to show iPhone apps, iPad apps, or all apps. you can also choose it to only show apps that have dropped in price, new, updated, and paid and free.
Best app finder iv used, and iv used alot. (love finding bargains lol).
Sent from my iPod touch using iPF