I have a 2002 Lexus IS300 5-speed manual, great car...always wanted one since driving the Toyota Altezza in Gran Turismo 2 on PSOne =)
Though it's not as powerful compared to other newer models that are out today it's still a great alternative comapred to the current E46 BMW 3-series in terms of power and overall value (when you factor in options and accessories). Great mix of sport and luxury, great handling and excellent brakes. The NA 3.0L 2JZ inline-6 engine inside the IS300 is very good...it will be missed when the next-gen IS goes V6.
Compared to other Lexus models, the IS300 is not as smooth, quiet, and roomy as the ES, GS, and LS...it's meant to be a little bit more on the sportier side, focusing on the driving experience. It has that 'Lexus' feel, but it also has a 'spirited' feel as if you can drive it like a go-kart =)
To be honest, though, if I waited a little longer for a new car I might have ended up with something else, but still I love my IS regardless =)
EDIT: Just read a press release of the new IS350...whoa, new V6 engine to make over 300hp, good stuff...it needs a manual transmission though! (IS250 has manual tranny)