I’m a poor grad student, so my situation is not quite like yours, but I do manage to travel despite not being in a great place financially. I get around it by being a cheapskate traveler, which works great but requires some flexibility (I’ve avoided kids and mortgages for the moment, thank god!) Of course my biggest plan is I travel in cheap places- I’ve decided to spend most of my upcoming vacation in Zambia rather than pricey South Africa, for example. You can travel reasonably well in China and India for less then ten bucks a night, and if you can scrounge up fifty bucks a night you can live like a king. I doubt I’ll ever get to Europe. But I have fun!
Right now, http://www.kayak.com is the place to go. It takes me a long time to buy tickets, because I look at every possible departure-return combination and will also gladly take cheap public transit out to whatever airport is cheapest to fly in and out of within a day’s travel. For example, I live in DC but my next big flight goes out of NYC. No problem- I’ll take book and a cheap bus up there if it will save me a hundred bucks. Kayak makes it easy to search nearby dates and other airports. To give an example, I just bought a ticket to Cape Town. Flying on my preferred dates out of my closest airport would have been over $2,000. But by messing around, I found tickets for $700. I’m seeing tickets to Nairobi in May for $800 right now, which is pretty awesome.
I’m seeing tickets on Kayak right now from $200. BWI is the only cheap way to go in DC, but there is easy ground transport into the city- a bus goes straight from the terminal to the metro (it does take a while.)
There are a number of airline special sites. If you are willing to be flexible about dates, you can find some awesome deal. My mom is a master of finding stuff like RT to London for $200. You just have to be at the right place at the right time and have flexibility about the exact dates.
To save money on the road- it’s all old backpacker tricks. I spend a lot of time sleeping in airports, browsing the cheap rooms on Hostels.com, taking local ground transport and eating street food and making picnics from exotic (and cheap) stuff at grocery stores. This doesn’t mean I don’t have fun. Most hostels have perfectly nice private rooms much cheaper than a chain- the DC Hostelling International (usually a classy operation) has doubles for $55, and there are cheaper private room if you don’t mind getting funky. I splurge on a few nice, truly memorable meals. But if the goal is “food in the stomach” I’ll go to the hotdog stand just outside rather than the museum cafeteria. I also tend towards low-cost attractions- I’m just as happy seeing the Kathmandu valley on a bumpy local bus rather than arranging an expensive guided trek.
Anyway, I live travel a bit closer to the ground than most are comfortable with, but that’s gotten me to 20+ countries. But even if you are not quite as flexible, there are still a lot of cases where you can get the same thing for a cheaper price.