Both STSDEV and VSeWSS are very useful tools that, in their own way, give you more simplified elegant development.
STSDEV is great in that it gives you a clean, class library project structure so that you have lots of control over your project. VSeWSS on the other hand is a customized solution template that allows you to automatically add in all the necessary files for common WSS elements (lists, content types, etc). I really like the ease of using VSeWSS, but I prefer the project structure of STSDEV. My solution is quite simple. Create your Solution with STSDEV (I usually start with a Empty C# solution with assembly) and then add in a VSeWSS project once you have the STSDEV generated solution open.
I basically just use the VSeWSS project as a file generator and once the files are created, I copy them over to the STSDEV project and begin customization from there. The only thing you really have to remember is to copy the Attributes.cs file from the Properties folder in the VSeWSS solution to the Properties folder in the STSDEV solution.
Of course, many people just have template files that they use, but this prevents me from having to go out to the file system to get template files.