I'm thinking of new clone with a bit of added features - features that wouldn't take up much space and give more to do with the base board.
IC: Atmega328
Form Factor: Slightly larger than the duemilanove
As of the moment i'm thinking of the following
3 LEDS + 1 RGB LED + 3 Switches + 1 LM35 / LDR + 1 TSOP
any more suggestions?
Why a clone versus a shield?
With a standard Arduino I can:
and I can
or I can
Why should I buy your board?
Sorry for the challenging reply, but the basic question to ask is: What do you want to build for who? If you don't share your perspective on this, then asking for a feature list is not likely to give you much value in return.
Ok. The idea is for beginners to experiment a bit beyond the blink as soon as they buy a board. I've come to realise a lot of people who are new to arduino seem to get lost beyond the led on the 13th pin and serial communication. So give them some more to play with only on the board?
I've thought about this in the past. I always try to convince myself this will work. But how is blinking 3 LED's different than blinking 1? I do like the idea of the buttons, but again, there is no challenge for even the absolute beginner to create a button out of some wire. Also you have to make sure anything that is built in will not interfere with shields or other peripherals that may be added on later.
You are on to something, but I think it just needs more. But I can't tell you more of what. Hopefully others will.
I think things like a thermistor, photoresistor maybe even a hall sensor would be great additions, very small and great for beginners.
I think a simple but very useful addition to add to a standard Arduino board is a I2C real time clock chip and possible an additional 8 pin EEPROM socket to the same I2C buss. Should be able to fit the standard footprint? might have to mount the RTC battery externally however.
Lefty
Adding an extra row of holes with 0.1 spacing so you can choose between using shields and perfboard would be a big plus.
But how is blinking 3 LED's different than blinking 1?
Perhaps implementation of the traffic light project will put in more confidence in the beginner and show some actual application. I find a lot of beginners get struck on constructing the simple hardware and then smply let go.The idea behind the tsop is so a tv remote(found in every house) can be used to do some magical controls 
I thought of the thermistor / lm35 but then thought light variation for the ldr would be easy to achieve over temperature variation.
I think a simple but very useful addition to add to a standard Arduino board is a I2C real time clock chip
Agreed. Will try to get this in. Though the eeprom might be a luxury.
Adding an extra row of holes with 0.1 spacing so you can choose between using shields and perfboard would be a big plus.
I agree. And speaking of this, why does the arduino have the funny spacing between the headers... It has been a question on my mind since first getting one but not something I have really looked into.
Its odd and I dont see the purpose.
Basically, someone screwed up when designing the first board, and everyone copied that.
a power switch
I think a simple but very useful addition to add to a standard Arduino board is a I2C real time clock chip and possible an additional 8 pin EEPROM socket to the same I2C buss. Should be able to fit the standard footprint? might have to mount the RTC battery externally however.
retrolefty, you just described Wiseduino:
And it's got a power switch as well 
retrolefty, you just described Wiseduino:
Wise time with Arduino: Buy Wiseduino kit
And it's got a power switch as well
Looks pretty nice, but seems to lack a programming port (no on-board FTDI chip)? I guess it's assumed one already owns a FTDI serial cable or breakout board?
Lefty
Thanks retrolefty. Right, no room for the FTDI chip (in the short version of the board), an FTDI cable/breakout is needed. Plus, it would be $6 more expensive. Plus, it's a DIY kit (many people dislike soldering SMDs).