Here's my initial specs although it might change:

• SSB voice and data, probably CW.
• Headphone/line out as well as a built-in speaker
• Mic in (probably an electret only) and line in/PTT line for sound card use
• Basic built-in CW "straight key" for basic morse and transmission for tuning
• Support for an external keyer
• Superhet, most likely single conversion but if image rejection is a problem I'll add another IF
• QRP level output (5W) and the capability to feed an external amp with pre-PA power (such as this)
• Basic controls on a simple LED/LCD display with tuner, power level, CW configuration, some memories, etc.)
• AGC and S-Meter
• Ideally a tunable IF filter, or at least a couple of different options