As of the fall of 2008 I'm about to embark on a new development cycle for a major product that has a winforms and an asp.net interface. We use Telerik, DevExpress and Infragistics components in it and all are going to have a release within a month or so which will be the one I target for our spring release of our product.
They all support VS2005 and we will continue to target .net 2+ so I can't see any compelling reason so far to upgrade to VS2008.
Has anyone found a compelling reason for upgrading to VS2008?
These are Microsoft's 10 reasons to upgrade (.DOC):
If you have a release within a month, I'd suggest not upgrading. Make the upgrade to 2k8 part of the next major release ... no reason you should risk something not working quite the same or some other complication if everything is working as is.
It is helpful in the particular case you describe. Consider the following:
1) You are at the start of a development cycle. It is always easier to make these types of changes at the start of or between cycles as opposed to in the middle of one. Given this principle, your next convenient time to upgrade (if the schedule is not delayed) would be next Spring.
2) VS2008 allows for the compiler to target any specific .NET runtime version including 2.0 if you need to continue supporting an older framework.
Also, as some of the other answers have suggested, go straight to SP1. The service pack upgrade experience was not nearly as big of an ordeal as VS2005 SP1... at least in my experience.
It's worth it. It's faster, the designer is vastly improved (split view, faster context switching), it has better support for javascript and when you're ready to target 3.5, you'll be ready to go.
I'd upgrade, but set aside some time for the install process. It took two hours on my moderately fast dev workstation, and I'm still doing updates, patches, hotfixes, two hours after the install finished... (haven't gotten any "real work" done today at all!)
I agree with Mr. Martinez in that I wouldn't port any existing projects up to the 3.5 framework, but the split designer and javascript debugging is worthwhile on its own.