If you are using nothing but Apple products, the built in apps will work just fine. You can set them all up to sync whatever content you like each time you plug them into your computer. Well, the iOS devices will work fine that way.
You can also keep the two computers synced using a MobileMe account. That will also allow you to keep the iOS devices synced without hooking them up. Everything except media that is. It is all very smooth and, for the most part, problem free.
There are a few disadvantages.
1) You must choose one and only one of your two computers to manually sync the iOS devices. While iTunes is happy to handle multiple iOS devices the opposite is not true.
2) If you already have content on your iOS devices but haven never synced them to that computer, you'll loose stuff if you are not very careful. Also, using third party apps and iTunes both is tricky. Be very cautious if you do this.
3) MobileMe cost $99 a year. While more trouble to set up there are other free services that will probably do what you want.
And alternate is to use a free service. The easiest to set up is Google. If you delve into the settings on your Mail, Address Book, and iCal programs you'll find you can add new accounts. Google is an easy setup.
You can also add a Google account to your iPad. The default method only gives you calendar and mail sync, but there is an alternate method that will sync Google Contacts.
Set Up Your Apple Device for Google Sync : Mail, Calendar, & Contacts - Google Mobile Help
{thanks to J0yful for the link}
Now besides this you may want a powerful ToDo list. There are several options that will sync across all iOS and OSX devices. Here are a list of some of the top contenders:
iPad Apps/Games : Best iPad Task Management Apps
I use Toodledo because I can use it on both my iOS and Android toys. It is limited to web access for the iMac though. But it's also cheap, as in free. At least for the web account.
And if, as you say, you are new to task organization and want a good way to start being organized I recommend getting [and reading] David Allen's 'Getting Things Done'. While you can definitely go overboard with the GTD method, you don't have to use everything he says to get good results.
Luck