You should incorporate firstbits into the system as well. That will make it very handy and better than most current online tools. Instead of remembering a whole Bitcoin address, the first 6-7 characters would do. Will make usability better as well (I know there's debate about whether firstbits are good or evil, but it would still be interesting to include that feature).
The Bitcoin wiki seems to view firstbits as a very negative thing. From a quick reading, it looks like yet another "Real Names" attempt, but this time for bitcoin addresses.
The wiki even says the founder of firstbits went around generating a bunch of addresses to get the "good ones".
That's not really their utility though. The value of firstbits is that you just type the first few bits of the address you want to look up and hit enter. It's like auto-complete.
Except it depends on that address being previously used. Otherwise people can attack it by entering a shorter prefix leading to another wallet. If I know you're gonna send to 1234567890, I'll go register 1234567899, so if you just type in 12345, it hits my account.
Any time a Bitcoin address is used for transactional purposes and appears in the
block chain, its firstbits - or the prefix that uniquely identifies that address
within the block chain - are considered assigned at that time. If another address
is created and used with the same prefix at a later time, the firstbits of that
new address will be at least one character longer, as the shorter prefix remains
reserved for the address that used it first.
I use https://blockchain.info/search/%s with keyword "bit" in Chrome, so I can "bit SOMEHASH" from the omnibox and it searches more than just address balances (transactions, etc)
The only way that I can think of to make it shorter would be typing x chars from the address and it would list balances from all matching addresses using auto complete (it probably only need a short part of the address to be unique) but of course most people probably use copy and paste and it would not matter
https://duckduckgo.com/?q=1Ez69SnzzmePmZX3WpEzMKTrcBF2gpNQ55