A Nokia 5310, before moving over to a ZTE blade gen1. Really liked the XpressMusic phones, and their proper headphone out and proper signal levels when using it. Trying to use the aux on car stereos with any following smartphones before my current Xperia 5 III was hopeless, since the maximum voltage levels were so low you had to turn the amplifier volume up to 11 just to hear anything…
For local usage on linux there’s virt-manager, has been good enough for my use at least, and the integrated spice client has relatively good graphics performance for normal desktop use.
Edit: don’t know about a good gui for running qemu on windows, though