QDX Transceiver
Recently, I bought an HF band (20m-10m) version of this transceiver. Most buy this as a kit, but as my soldering skills are poor these days, I got this ready made from QRP labs. It is a 5W digital transceiver that can be used with WSJT-X. It is tiny, yet has been copied al over the planet despite the simplest of antennas being used. My antenna is just a low end fed antenna. I can thoroughly recommend this transceiver.
A version is also available for lower frequencies.
In my experience 5W is quite enough.