Actually, the easiest way to do this would be to put all your system service
accounts in a separate OU and exclude  that OU from the import. That's
normally what I recommend.

Well, we could do that - but we have all our offices (3) in different
OU's and I have no idea how to add all 3 OU's (or exclude  the one
with the system accounts) to the profile  import AD query.

From Shared Services, user  Profiles and Properties, import  Connections,
you can create a new custom import connection. Select Active Directory
Resource and only put in the OU with users. For 3 OUs, you would need to
do this 3 times.

Or

In the existing import connection, you could filter out any information
you want. There is a filter section in the middle of the config screen.
But, I do not know how to configure  an AD filter. I would assume you
could write a filter that excluded any accounts without email addresses.

That's exactly what I want to do - filter out those pesky system
accounts from our SharePoint environment :)

The thing is, as mentioned, we have 3 OU's:

Oslo - mainly user  accounts, but also a couple test users
London - mainly user accounts, but also a couple of groups and server
accounts
Houston - all sorts of accounts and users

So, until we clean up our Active Directory (btw, does anyone know if
moving around on users  and creating new OU's will affect the users in
any kind of way?) I'd rather filter out those accounts that does not
have an e-mail address.

This blog will tell you pretty much what you need to do to import  from
multiple OU's

blogs.officezealot.com/.../8317.aspx

What can go wrong moving accounts between OU's ? Depends on how AD is
set up but off the top of my head there are 2 pretty major things

If you have dynamic distribution lists setup for sending mail around
then people will move distribution lists or be removed from them

If you are using GPO's to control your environment then they may be
subject to a different GPO if they're being applied at OU level and so
will get a different desktop experience - at its worst, if you are using
GPO's to install software on users  machines then when you move the users
between OU's they may find their software is uninstalled !

Also, Active Directory delegation is applied at the OU level.

we had the same issue. I was able to convince our AD
administrators that it was worthwhile reorganizing our OUs for this. All
of the accounts for whom we want profiles imported now fall together
under one parent OU.

- domain
- OU 1
- Users
- City Users
- OU a
- OU b
- Contractors
- Generic Accounts
- Service Accounts
- Security Groups
- etc...

We're importing from \Domain\OU 1\Users\City Users and it's children.

This reorganization involved re-applying some group policies. Ben's
solution (specify multiple profile  imports) is probably better.

I get using tabs for indents doesn't work! I've edited below...

You might find this useful

www.sharepointblogs.com/.../9462.aspx

That's exactly what I was looking for. But, no matter how I try
to set the query up it either tells me that:

"The query is not valid based on the specified search base and search
filter. Please validate your input of search base and filter.",

"One or more values typed on this page are not valid. Check the text
for the indicated fields.",

"A test import  based on current input returned no results. Please re-
check the search base and filter." or simply accepts the filter, but
returns all profiles and system accounts.

Does anyone know how I can combine the (email=*) with the rest of my
filter?
Here's my current search filter:
(&(objectCategory=Person)(objectClass=User)(
!(userAccountControl:1.2.840.113556.1.4.803:=2)))

It's easy way:
For example Look below
(&(objectCategory=Person)(objectClass=User)(memberOf=CN=container,ou=companyname\
,DC=domain,DC=com,DC=pl)(mail=*))

With a little modification I achieved exactly what I wanted. Only
import user  accounts with an e-mail address and do not include
disabled accounts:

(&(objectCategory=Person)(objectClass=User)(
!(userAccountControl:1.2.840.113556.1.4.803:=2))(mail=*))