La Campagna on Main St.  Or Tuscan Grill on Moody.  Both great.

For basic, family style italian, The Chateau is considered an institution in Waltham.
http://www.chateaurestaurant.com/

On the high end, I visited La Campania a few months ago. Quaint atmosphere, food was tremendous. Location is on Main St. directly across from that great greasy diner.
http://www.lacampania.com/

I have also heard great things about Il Capricio, but have not been there.
http://www.ilcapricciowaltham.com/index.html

I would suspect foodyguy may have other suggestions.

Mangia E Statti Zitto!

Il Caprici -- best by far if you are a food lover

I can vouch for Il Capriccio and Tuscan Grill.  Here are the Zagat ratings for their top three Italian in Waltham


                Food  Decor Service  Price

Il Capriccio      27     22    25      $58
888 Main St.
(Prospect St.)
Waltham, MA
781-894-2234
 
La Campania        28    25     26     $59
504 Main St.
(bet. Cross & Heard Sts.)
Waltham, MA
781-894-4280

Tuscan Grill       24    18     20    $45
(bet. Spruce & Walnut Sts.)
Waltham, MA
781-891-5486

The Chateau:  Unless things have changed in the last year or so, this restaurant is far from a gourmet's retreat.  And not quite a romantic stop-off.

Il Capriccio:  Classy.  Great wine list.  Start out at the bar; and then proceed to a romantic, white tableclothed table.  Get advice on which entrees to order from the more articulate of the bartenders.  Your primi or secondi will be heavenly if you hit it right -- dull, if wrong.

La Campania.  I've not tried it, but I've heard very good things from beyond this board.  

Tuscan Grill.  Oh, shucks.  During the winter both the chef and Sylvain, the superb bar manager, have bailed from this previously outstanding eatery.  There's a new chef and a new menu.  All the old ratings need to be reaccomplished.  

Biagio.  Moody St. by the RR tracks.  Never tried it, but some rave about it.

Looks like you've gotten some great responses in Waltham...  Depending on your definition of "near" I really love Sweet Basil in Needham (about 15 minutes from Waltham).  The food is amazingly good.  Portions are too big.  A couple things to know if you try it out.  1) you need to bring your own wine (they charge $5 corkage) 2) Cash only (prices are very reasonable with the most expensive entrees around $20) 3) No reservations so you might have to wait for a bit (but if you tell the hostess your hungry they'll probably bring you some Bruchetta), 4) No dessert - but if you really want something, walk over to Not Your Average Joe's when you're done...  The chef/owner is Dave Becker - very nice and personable guy - you should ask to meet him (but probably will anyway).

Enjoy!

I agree, La Campagna

If you are back in the area, you should try Jake and Earl's or it might be just Jake's Dixie Roadhouse.....some of the best BBQ north of the Mason Dixon.

As far as Italian goes, Il Capricio is also right next to Gordon's Liquors......great wine selection and also has a test kitchen inside that they do demonstrations and classes sometimes.