I bought an older bike with DEORE XT thumb shifters and I am wanting to upgrade to newer componets. Any recommendations? The rear is a 7-speed with a tripple on the front. Also, are there brifters that shift a 7-speed? May want to go to drop handle bars. Any good ideas appreciated.
There is no upgrade from what you have which will enable you to remain with 7 speed. Cycling has moved on quite a way since 7 speeed XT and the only 7 speed stuff available now is the lowest grade available. Current XT is available for 10 speed. I'm not sure what you've spent so far but an upgrade of that sort can cost four to five times what you may have paid for the machine in the first place.
I'm not sure what kind of bike this is (given it has XT, I'm guessing a MTB or commuter), but regardless I wouldn't advise switching (from flat or riser bars) to drop bars. The frame geometry isn't intended for that purpose. Just beacuse it's possible doesn't mean it's advisable. Moreover, there are no 7 speed STI style shifters available.
In short I think you may well be better of with a new bike (or a newer used bike) than upgrading your current one. The frame and components will be newer and likely to cost you less as an ensemble than the total cost of sourcing ad hoc upgrades.