Pro tip: *Always* record your sources, for every scrap of info (GRAMPS lets you do this), that way when (Not "If") you have conflicting pieces of information, you can figure out which one to trust. GRAMPS also lets you assign a 'reliability' to each piece of information.
The only problem is that exporting to GEDCOM format loses a lot of this kind of 'extra' data. (IE, exporting is a lossy process, so use GRAMPS as a master, and if you want to put your tree online, use that as a secondary source for family members to add to.)
As far as resources go, Ancestry.com has a bad habit of suggesting that they have a ton of matches in all these different databases, when in fact most of the matches returned don't have any relation to the names you entered. Don't base your decision to subscribe solely on that.
That being said, many public libraries offer free access to some, or many, census records and other public databases.
If you have Swedish ancestors, GenLine is EPIC: Digitized church records (Swedes often had data recorded annually instead of every 5 or 10 years, and also recorded moves into and out of parish districts.)