Ginza Tenichi (Shibuya Tokyu Location)
Ginza Tenichi is on the 8th floor of the Tokyu department store. It is the sister branch of the popular Ginza tempura restaurant. The price is higher than most tempura joints but you do get noticeably higher quality tempura here! Order the seasonal special platter (3,564 yen) and you're in for a feast. For something a little more affordable, try the ten-don (tempura on a bowl of rice) for 2,052 yen.
Temmatsu is located near the Shibuya Station, on the 9th floor of the Tokyu department store (Toyoko location). For 1,680 yen you can have a ten-don which comes with a miso soup. If you want something more special try the special set meals called ume (1,680 yen), take (2,100 yen) and matsu (3,150 yen). They are all excellent and come with a variety of side dishes. The price difference is due to the amount of tempura you will get.
Tempura Tsunahachi (天ぷらつな八)
Tempura Tsunahachi is located on the 8th floor of a building. The place is very popular for lunch and it is not that expensive for tempura cuisine. You really get the bang for the buck here. It's quite easy to figure out what you want since there are meal displays at the entrance. The of the meals range from 1,000 to 2,000 yen.
Shinshuya is located a 3-minute walk from Shibuya Station's Hachiko Exit. This is the place to go for amazingly cheap soba dishes that are surprisingly good for the price. Tempura is a common accompaniment to soba. You can have a soba bowl along with 5 pieces of tempura for just about 500 yen! Most of the items on the menu are around that price. It's one of the most popular and well-regarded shops on the very low end of the price range in Shibuya.
Tendon Tenya is a popular chain of tempura and soba dishes. The best thing about it is that it's really cheap. You can get a tendon such as the one pictured below for 750 yen. It comes with a miso soup. If you're really hungry, you can also get some sets with a tendon and soba noodles that come with a soy-based dipping sauce. These cost about 1,000 yen.
So if you're looking for tempura in Shibuya, you have various options from cheap and satisfying to pricey but refined. If you happen to be in Asakusa, here are some other restos worth checking out for tempura.