Ever since the Basic Mode of the Second Life viewer was introduced, we mentors have had to wage a fight against it. One of the first things we're asked, over and over again, is "how do I change my appearance?" We've had to tell people, "Well, first you have to quit Second Life, and switch your viewer from Basic to Advanced mode..." Telling someone to leave the virtual world almost before they've begun is not really the way to enhance their "first hour" experience!
Linden Lab seems to have finally gotten that message. The latest viewer, 3.0.3, now has a Basic/Advanced switch in the upper right corner, near the clock and $L balance buttons. I'd say "kudos!" except that it should never have been needed in the first place. Still, it's a step forward.