Littlemoe,
I picked up a 1/72 scale spitfire a few years back and had the same reaction - this thing is tiny !
From what I've read on this site - I'll assume that I'm more representative of the bottom edge of the "most modellers" bell curve. I build most everything from the box, never purchased a detail set of any type, usually buy stuff of the less expensive (raised panel lines) variety. The only "aftermarket" thing I've purchased was a decal set for an ancient P-47 kit whose decals looked like they had been printed on papyrus.
I tried re-scribing a 1/72 Tempest once and I had to call it quits after I finished the bottom of the wings. It was allotta work - probably because I didn't have the right tool for the job. I've heard of scribing knives/tools out there, but I haven't bought one. I'm content to live with raised lines when I get them - even with the 1/48 scale stuff that I do.
I think there are other things that can be done to make the model much better looking/more realistic than simply re-scribing lines. Carving/drilling out duct holes & drilling out exhaust pipes (and gun barrels on 1/48 scale) are things that I have done just in the last couple years. Pin drills are a beautiful thing.
An eye dropper and white paint is a great combination tool too. I read about "scaling" the paint colors a while back and I think that it has made my models look much more realistic. The smaller the scale you build in, the more white you add to the paint mix - so for 1/72 and smaller it is more significant. It just looks more realistic that way. I usually use three drops of white for every 10 drops of other color.
I've seen paint washes on a raised panel line model that made it look incredibly real. In fact - I think it was in FSM ! I'm still working on being able to do it myself - It needs more work - but it's getting better.
Like others have said - have fun !