The Space Pens are nice but seem to be carefully designed to slip out of pockets - I think I've lost four bullet pens by now. My pocket carry at the moment is a Tombow Airpress, which gets the same or better performance as a space pen simply by pressurising the refill every time you click it. It's also got a nice rubberised grip, the pen costs £6 odd and the refills cost pennies.
As a full sized normal ballpoint the best one I know of is the Uni Jetstream, which won in a survey of pen bloggers recently. It has all the best things from gel pens and the best things from ballpoints and it's three quid in Rymans. The Schneider Slider Memo biros are also really nice writers, comfy to hold and come in lots of colours.
Classiest one is the OHTO Promecha which makes me feel like a Swiss architect every time I take it out. Also very fine point if you like that sort of thing.
http://www.cultpens.com/acatalog/OHTO-Promecha-Ballpoint-Pen-NBP-507R.html