Add your own to the forum, then we shall add them here.
Here's a few we came up with to start things off...

More integration/compatibility with excel... (file or copy/paste etc)
alerts - import and export of all alerts
portfolio - import and export of all portfolio information, symbol, quantity, price, notes
pointer - improved pointer conbining both pointers
have the same charts alerts trendlines on there machines
portfolio - similar to the email flags in outlook express....flags and watch tags
first bar of the day still starting at close - gaps not showing
updates... placing old versions in a folder
beta versions... update process should include a backup of data should the beta be duff and loses data, can be a problem if the user does not have access to adequate backfill and manual trendline etc can be lost
should be easier to have a roll-back option
option to switch the default charts from intra to history
history - percentage measuring tool or line
history - spike filter not carrying across to history, needs checking on change of filter and clearing historydid not remove spike
dotted/dashed trend lines
intra-day charts - option for % scale on left of chart
0% being at yesterdays close
intra-day - opening bar still not correct, opening gap not showing with some feeds
similar to windows "show desktop" a button that takes away all charts and then brings them back again
portfolio - revolving charts at a set speed
portfolio - manual keystroke revolving charts
auto 2 color schemes 1 for intraday 1 for historic
double click to open historic as default option
better use of "Notes" option to have notes displayed instrad of price tooltip
better use of "Notes" option to have mouse-over of the symbol to display notes