Mine is easily Paul F. Tompkins. The guy is an excellent comedian and improv actor plus he loves video games. He also seems reasonable attainable since he seems to pop up as a guest on the most random podcast and does quite a few shows every year in the Bay area.
I also got a dream guest for the Beastcast and that would be the McElroy brothers of My Brother, My Brother, and Me and The Adventure Zone podcast fame. Plus two out of the three brothers work for Polygon so they know their video game shit. So who are your dream guest?
Here's a clip of Paul F. Tompkins talking about Bioshock Infinite in an Irish accent just because.