Top technology investment banks
By this, I assume you mean banks that have exceptionally well renowned coverage practice focused on technology companies.
As with all coverage areas in investment banking, there is no simple answer. In part, because it depends on what part of technology and what areas you are focused on.
In terms of broad technology IPOS and M&A, across both internet and areas like big tech - Morgan Stanley and Goldman have very established tech practices, significant deal flow and are typically top of league tables (although league tables depend on what you are looking for and how you cut it). Other bulge brackets like Citi, CS, DB and others have respectable practices and MDs with excellent skills and client relationships in specific parts of tech.
Among boutiques - Qatalyst, Allen & Co. and a few others are known for strong tech M&A and are typically on big ticket deals.
All that said - whether you are looking to hire a bank, or looking to get recruited into one - you need to dig deeper into the specific part of tech you are focused on, the specific products (M&A, equity, debt) that you are focused on, and the specific teams at those banks you will likely work with. Moreover, banking talent tends to move around and that can impact your decision as well.