Hi all,
I've been commuting 2-4 times a month with my fuji absolute 2.1 for almost 3 years. It's a long commute (for me) - 22 miles round trip. I figure I've put somewhere between 1500 and 1800 miles on the bike. the bike rides fine although it is squeeking a bit. I've put some 3in1 oil on the chain occasionally which now has led to some nice "cakes" of black squack on some of the gears. So, i figure it's due for a chain cleaning at least.
Questions:
1.is there an oil other than 3in1 I should use?
2. any other maintenance that should be done to prevent an epic fail on the road? I carry stuff for tube replacement and some tools at all times.

1) chain lube questions take on a religious tone at times. There are a variety of answers from don't do anything until it's time to replace the chain to complicated cleaning and relubing rituals. Either way, the goal is to prevent increased wear on the cassette and chainrings.
2) brake pad and cable replacement would be a good start, followed by checking the operation of the derailers and checking the tightness of all the bolts. Replacing the wheelbearings makes sense at times, and you've probably gone far enough to justify that.

1. Bike specific wet or dry lube.
2. Assemble everything properly and sudden failure from parts breaking should not be a concern for a long time. Failure do to wear and tear could be anticipated during use long before the parts fail. Check common things like tires, brakes, chain and drivetrain etc.

1. There are a lot of different oils, waxes, and dry lubricants for your chain. Just ask at your local bike shop - they'll have all sorts from cheap to wallet-clenching expensive - and select an oil they recommend. No need for anything expensive; all my road bikes get treated with an oil that cost less than £10 for a decent sized bottle.

2. Regular maintenance - as above, check the tyres, drivetrain, brake cables and pads. With brakes the rule is if in doubt replace - a set of pads or a new cable is cheap, and if you're not sure about fitting them get your LBS to supply and fit.
Clean the drivetrain regularly - if you're commuting in bad weather it'll get dirty very quickly and a chain cleaning bath plus a set of brushes will get everything running quietly and smoothly with 15 minutes work.
If you've not got one already a chain breaker tool is worth carrying - I've only needed to use mine once but I was 20 miles from home. It's essential if your chain snaps and can be useful if your chain wraps around the crank.

I commute on a "vintage" steel road bike. The same style road bike I commuted on when this style was new. I try to ride on dry days, and have always kept my bikes very clean. It is really easy for me to disassemble the bottom bracket, hubs and headset to clean and regrease the bearings. I use motor oil and WD-40 to "oil" parts that need it regularly. It is what we used in the bike shop I worked in as a teen. I true the wheels, and adjust the cables as needed. Tires, tubes and brake pads get changed when needed. Components also get changed if needed. I keep a sufficient size inventory of spare parts and supplies on hand. So...keeping a bike super clean and lubed, looking it over when you clean it and lube it, and keeping up with scheduled maintenance is the way I would describe it. Good vintage bikes are good for many thousands of miles. Plus, avoiding pot holes in the road can add thousands more.

Chain Maintenance

This site has lots of good information. I am sure you can google "regular bike maintenance" and find articles on what type of periodic maintenance you might want to do. The Mechanics Forum on bikeforums might also have some stickies!

1. yeah bike chain lube is better and not that expensive given how little you have to use. Everyone has their favorite brand but it doesn't really matter than much, just clean it and lube.

2. Everyone has mentioned cables, after 3 years the cable housings might need attention.

A quick check every ride (ideally, but realistically every few) can keep you on top of the maintenance. ABC - quick: air, brakes, cables/chain, quick releases. "Air" includes checking the tire for wear, bulges, thorns etc. Brakes: pads, adjustment, not rubbing during a free spin, and testing them when you first get on. Cables fraying at the clamps, corroded, not coming loose, excessive resistance in the housing. Chain, as you're doing is it nasty, makes noise, also after 1500-1800 miles you might check the chain 'stretch", 1/8 inch beyond a foot link-to-link means replace it. Quick releases on the wheels, ensure that they're tight and the wheel is straight.

The full quick check takes a minute realistically and gives me an idea of needed maintenance before I'm actually surprised by it. I don't do it religiously, sometimes just a quick tire check and glance at the brakes, but it's a good habit.

Replacing wheel bearings? That's way overboard. If the wheels spin without squeaking or crunching, leave 'em be. I commute ~2000mi/year and haven't touched my wheel bearings since I bought the wheelset 5 years ago.

All the rest of that advice is good though. Don't get sucked into the Chain Lube Holy Wars. Just pick something reasonable and use it as often as it needs to be used (listen to the chain, it is either silent, or it is saying "lube me!").

There's a spectrum between long-lasting lubes, which are dirtier, and cleaner lubes, which need to be applied more frequently. If you've gone 1500-1800 miles and are only mildly perturbed by built-up "cakes of black squack", I'd guess you live towards the end of the spectrum that would tolerate dirt in exchange for duration. The gold standard there is Chain-L.

If you want to be able to use your cassette for a dinner plate, the extreme in that direction is to strip the chain of all oils and periodically soak it in parrafin wax. For this you typically keep a dedicated crock pot of wax. Every few weeks you'd flip the switch on the crock pot to re-melt it, take your chain off the bike and drop it in (on) the wax. When it's melted and soaked for a bit you take it out, turn off the crock pot and put the chain back on. You would need a chain with a quick-link of course, and special quick-link pliers would be worth the investment, and used crock pots are plentiful and cheap at thrift stores. Wax zealots swear it's not much effort, but I prefer to not even think about my chain for 3-4 months at a time.