Their latest research confirms that all channels play a role. This summary taken from an public piece available here.
- The branch and the Web are the key buying channels. When it comes to researching a new product, 47% of consumers prefer to use the Web, and 35% prefer to visit a branch, far outpacing other channels. For opening a new account, nothing comes close to the branch — 82% of consumers prefer this channel.
- The Web is a top channel for day-to-day banking. Roughly one-third of consumers prefer to use the Web for checking account balances, viewing account statements, and transferring funds between accounts.
- The branch is the top service channel. Consumers most frequently picked the branch as their preferred channel for changing an address, getting help with an account problem, and disputing a fee.
This research is based on Forrester’s quantitative Technographics research. Some additional supporting findings.
- The Internet appeals to younger generations. When it comes to the adoption of online banking activities, younger is better. Except for some minor exceptions, the preference level for the Internet decreases with age for every activity.
- Gen Xers have the largest Internet gender gap. Males who are Gen Xers or older are more likely than females of their own generation to prefer the Internet. The widest gender gap for every activity is in Gen Xers.
- Seniors are all about the branch. For most of the activities we examined, Seniors (both males and females) show the highest interest in conducting business at the branch.
- Young consumers are split by gender on the branch. For most activities, Gen Y males show a higher preference for using the branch than their female peers do. Interestingly, the opposite is true for Gen Xers, where females are more apt than males to use the branch.
- Phones are a female thing. Females prefer to use the phone more than males do — across every generation. The only exception is that male Gen Yers prefer to use the phone for researching a product more than female Gen Yers do. This same pattern is true for automated phone systems.
Bankwatch 
Cost v/s Effectiveness
To my mind, this information highlights the perennial businesss dilemma between cost and effectiveness. I suspect that most banks would be happy to do most transactions on the web, for cost efficiency reasons. What leaps in imagination would be necessary to make that channel as effective as say, the branch is today, for customers who wish to open a bank account? Can existing tech like Instant Messenger software make it more “touchy-feely” and “human” and therefore more likely to be chosen by customers?
Dead on! We need things like, IM, push to talk, and secure email comms direct to your relatonship manager/branch.
Whats lacking is the connection people and technology. Online banking sites have been built like ATM’s assuming only basic transactions, and now that we want to integrate the people into the equation, the technology infrastructure is not there.
But this is the right strategy, and the interaction between bank employees and customers online is part of the next level of online banking capability.