I run two drill motors in my machine, as do many roboteers. Whilst I have no battle experience (thank you, cheap ebay speed controllers) they seem to run perfectly fine. Team Expat (who are behind the Tormenta series of robots) use 4 drill motors in their robots, they've got a few guides on their Youtube channel (TeamExpat) on how to hack the drill motors yourself - really only takes a screwdriver and some m5 grub screws, then obviously your mounts. You might also need to get some replacement gears as a lot of these come with plastic gears, which obviously aren't the greatest of things and shred quite quickly, but they're easy enough to get a hold of I believe.
The gimsons are great if you want something that's all ready to bolt in, which is definitely what I'll be doing for my next robot because I have no workshop other than the kitchen worktop itself - they are however, more expensive than simply modifying the drills yourself... All depends on your budget, really. There's also ones that you can buy from BaneBots too that have various different ratios for speed/torque or whatever.

I've heard many good things about the TZ85As, too - if you've got the money for them, I really don't think you could go far wrong - I'm fairly sure they're pretty widely used. Again, you can buy the brushless ESCs and hack them yourself if you have the kit to do it and know what you're doing which is a lot cheaper than buying them from BotBitz but it's also more difficult as you could imagine. I've bought some '320A' ones off eBay that are significantly cheaper (mine cost about £26 total compared to nearly £100 it'd cost to get some of the BotBitz ones) and are similar ones to those used in Scruffy and Night Fury, but I think I may have got a different model as mine have a brake function in, and naturally isn't the sort of thing that's preferable in this kind of application...

Long story short, look for something that's forward/reverse, or is programmable to get rid of any brake function- you don't want only forward, and you don't want forward/brake/reverse either because that can be a bit of a pain.

Finally, for batteries, most people run LiPo, I believe, up to about 6s (24V, there abouts) which the BotBitz ones will definitely handle. Motors can definitely be run about the rated voltage, but the general rule is about 1.5x, so if you had the 18v Gimsons, you'd be able to get away with 5s or 6s LiPos, but of course if you had the B&Q/Argos drills then you'd only be able to go for 5s (about 18v) at most, again depending on the speed controllers you go for.

If budgets weren't an issue, I'd personally go for 5s/6s LiPos, some of those BotBitz hacked TZ85As and some 18v Gimson motors, then some of those BaneBots or RoboChallenge wheels too, but there are alternatives.

I'm definitely not an experienced roboteer, but I hope that helps you out a little bit!
And when in doubt, always have a look at the build diaries section, always some great tips to be found there, helped me when designing HardWired!