It still isn't quite as elegant as webOS's take on multitasking, but Itching Thumb by Johan Cloetens is a nice task manager option for your HTC EVO and definitely a big step up from Visual Task Switcher (VTS).
For starters, you can flick a card/preview off the screen to close the app, which was one of the most well received features of webOS Cards and what many hoped VTS would include. Itching Thumb also lets you choose the style in which the running apps are presented (flat, condense, or carousel) and assign gestures to apps so that you can launch them later. In addition, long pressing a card brings up a context menu that gives you an option to uninstall the app if you decide mid-run that you don't want it anymore. You can choose to go to or kill the app from this menu too, but it's faster to tap a card to go to the app and more fun to fling it off the screen to kill it.
Some of the features aren't working like they're supposed to on my EVO (rooted, Froyo, SteelROM Rev G with Sense) for some reason, but you may have better luck with it on yours. QR code below.