During the legislative session, first thing each morning or last thing each night I go here to see what bills have been filed that day:
The LinkIt's a trustworthy source for legislative information, since it is, well, what the legislature uses. I also use it pretty extensively for statutes and the Texas constitution, since generally I know what I'm looking for and where to look.
For the Texas Administrative Code (which I use quite a bit), I always use the Texas Secretary of State's website:
The LinkAs I understand it, the Texas Register is the authoritive publication, but I don't go back to it. I also don't track down the usually out-of-date books, if they're still published.
For IRS publications, I either check my deskbook or go to the IRS website. Same for SEC stuff, and of course all of us use the MAC now for researching continuing disclosure information on clients.
I don't do much case law research, but I tend to use the internet all the time to review statutes, IRS material, SEC material and administrative rules. And for legislation. Every day the legislature is in session. And then I'll ramble through TASA and TASB and TML and TAC to see their bill analyses. Mighty handy.
Now for Wikipedia, I usually go there for descriptions of starlets I've never heard of, and for short biographies of writers I've never read. On both I've found it trustworthy enough for my purposes.