I honestly have to recommend that you buy the work bench top pre-built. You can buy these for about the same cost of the raw material itself. The ready built ones are beautiful, nicely sanded and sealed with rounded edges. Look for work bench tops at certain online business supply places. Tops can be found that are about 1.75 inches thick which are very sturdy. A typical top is 60x30 inches in size.
![enter image description here](https://i.stack.imgur.com/HTyba.png)
As I recall the IKEA ones are way thinner. Maybe 1.00 or at most 1.25 inches thick.
A web search will turn up many sources. One name to keep an eye out for would be ULINE.
I agree that for cutting 2 x 4's you absolutely do not want to use a jig saw. While a jig saw is handy to have. As Ed mentioned, you cannot get square cuts and are generally used for thin material and scroll work unless you shell out the money for a professional model with massive power.
A compound miter saw is a better choice than a chop saw. I believe that Ed may have been describing a miter saw but wanted to point this out as they are two very different things.
A chop saw is 'like' a miter saw in that it allows you to make 90 degree cuts in materials but is usually intended in a shop environment for chopping metals.
A compound miter saw allows you to make angled cuts from over 45 degrees to straight 90 degrees perpendicular to the work piece. It also can tilt to make angled cuts at varying degrees. The compound part allows you to do both at the same time. The sliding part allows you to make cuts while the blade slides on a rail allowing you to make wider cuts than a typical miter saw. You can cut 2 x 10's with a sliding version where you could only cut 2 x 6's with a non-sliding version.
You can pick up a very good entry level compound miter saw at your local Lowe's and Home Depot's for around $130 (7 1/4 inch versions - may not handle 2 x 10 cuts). While they have a slightly bigger footprint than your average manual miter saw/box combos you will get much better and lightning quick results. Plus you will find that you can actually do a lot more around the town home with it.
And best of all, these work just as well on the floor as they do on a work bench.
If a small hand unit is all you really want however. Get a power saw (a.k.a circular saw). You will get square cuts (no blade curve) and will take a fraction of the time. Not as accurate as a miter saw but much better for 2 x 4 than a jig saw. You'll save time and have better cuts using a framing triangle with the power saw.
Hope this helps.
Best Answer
Any common butcher block countertop can be cut and rounded to fit. You'll have to refinish the sections you've cut, but there are no other special considerations. Cheap tools are often OK for one time jobs, there are also tool libraries where you can rent or borrow better tools. Some home stores offer rentals.
For finishing butcher blocks, the traditional materials are some form of food safe oil. For a desk you have the option of sanding and using any sort of furniture finish from a wax to a varnish to polyurethane. It's best if you buy the butcher block unfinished, so you don't have to match finish. An excellent discussion (focused on food uses) is at http://www.thewoodwhisperer.com/articles/cutting-board-finish/