Everyone will just recommend their own favourites, nothing wrong with that, but you are unlikely to get much of a concensus.
The dac part is easy, a Behringer UCA202, not the UCA222 which is mpre expensive and comes with software you neither need nor want.
Add any of the sub £150 amps from Richers, whichever you prefer. You will get multiple inputs and remote control. The UCA202 plugs straight into your computer usb, you will need a pair of phono leads, probably not supplied but decent ones can be had for £10, Use mains cable for the speakers, preferably 30amp 'twin and earth' (see recent 'Solid Core' thread), a local electrical shop can supply this for no more than £1 per meter.
The PopPulse has something of a reputation but is absolutely basic, no input switching, no remote etc. Worth a look if that works for you.