I think if the argument is for a ~Y5,000/night business hotels or ryokan located in & around Shibuya being perhaps a better deal for fashion-centric SF members than a backpacker hostel or ryokan up near Ueno or Asakusa, I would be inclined to agree. One challenge is that most business hotels in and around Shibuya, Harajuku etc are well above the Y5,000 mark. However, if willing to take go a bit further out toward Ohashi (as impolyt_one indicates), one might consider places like the Hotel Fukudaya
which has rather spartan singles starting from Y5,250... At almost double that rate but with a lot more corresponding amenities is Hotel Excellent
in Ebisu. And, yes - I know Ebisu is not Shibuya but it has a nice selection of restaurants, a decent vibe, plus a decent sports bar (Footnik), pub (What The Dickens), is on the Yamanote Line and is one stop from Shibuya. It also comes recommended in this NYT article Two Days in Tokyo, Stretching $500 Worth of Yen
Oh yeah, and borrowing Tokyo Slim's excellent map, here is a brief outline of an afternoon I spent with American friends who were up for one day in Tokyo before flying up to Hokkaido for skiing end of last year (outlined in purple):
We started at Harajuku Station just before noon, made a perfunctory visit to Meiji Shrine, looped back to Oshman's for some ski wear required for Hokkaido, then a walk down Takeshita Dori. Headed toward Omotesando and broke for lunch. One group wanted to do more shopping in Omotesando and the back streets like Cat's Alley, while I took the rest to Shibuya for some Christmas shopping. Tokyu Hands, a boutique t-shirt place, the Apple Store for a handful of iPods. Coffee at Starbucks to look at the scramble kosatten and for a weird reason, a sushi break consisting of only prime cuts of tuna (chu toro, toro etc). Back to the t-shirt shop and more walking around and then a taxi back to the Grand Hyatt in Roppongi Hills in time for drinks and dinner.