Personally speaking I've never found a particular package that I'm satisfied with using. They're either not comprehensive enough, too black box or generate reams of pages of calculations that are a mess to check.
I generally prefer using spreadsheets, but I think theres scope for someone to develop something much better that is simpler to use and is more transparent/graphical.
I tend to agree with @ukbridge. Any steel design software I've used has been bundled with an analysis program (so that's convenient...) but there are always small nuances that need to be dealt with before the design can proceed. This is especially true once you consider the connection design. Lots of programs have a hard time with offsets/work points and how that will affect the force distribution. Take some time and make a thorough spreadsheet.
LTBeam is a neat little piece of free software. It won't do code checks, but will give you an accurate elastic critical moment (Mcr) for any loading, section shape, restraints etc.
Alex Tomanovitch's Spreadsheets are possibly one of the greatest gifts to humanity. He has loads of all manner of spreadsheets that he must have spent his entire career developing.
Specifically what you are looking for is a spreadsheet called BEAMANAL.xls. AISC code checks for all types of loading on W, C, and MC shapes. That is one of about 70 of his outstanding workbooks.
I'm not sure if he's still developing but a few people - Joel Berg, David Taylor - have been keeping the sheets alive (i.e. updating codes and reposting). It's strange to say this, but Alex has been what amounts to a mentor in terms of my spreadsheeting standards and style, just by studying them.
Enough gushing. There are tons of other great contributors to the spreadsheet world. Steeltools is an excellent resource.
