If you've ever looked at the stock battery icon in your Dell Streak's taskbar and wished you could see the remaining battery percentage as an actual number rather than a diminishing colored bar, then you should know that MoDaCo forum member Gopu has recently revealed himself to be part-genie. And yes, he's made one of your wishes come true.
As long as you like the way it looks and your Streak is running the venerable DJ_Steve's custom Froyo ROM without kikamal's theme, then you can replace the stock icon with the circular battery icon, complete with gradient color fill and numeric percentage, shown in the "after" shot above. It may be possible to get this working on other builds, but it has only been confirmed to work on version 1.4.6 of DJ_Steve's ROM.
Anything you do to your Streak is done at your own risk.
I've provided written instructions on how to flash a .zip several times before, but here's the tutorial again, this time in HD video form. Note that the method is not exclusive to this battery icon tweak; it's just the standard procedure for flashing a .zip or ROM (which is also a .zip file) on the Dell Streak.